If there weren't moments (and even an entire hour at the end of the miniseries) when he actually had a clue and wasn't screwing things up, Tony Lewis would actually be Too Dumb to Live. With those additions to the character, he just carries the Idiot Ball for the entire adventure only to finally drop it during the assault on Wendell's castle. But the most obviously idiotic moment (aside from breaking the magic mirror) has to be in part one, when he proves he definitely never paid attention to Aladdin or any other wish-granting story. For his third wish on the dragon dung bean, he wishes for a vacuum cleaner which would clean the entire apartment so he would never have to lift a finger... even though for his first wish he caused his building's superintendent and his entire family to become his slaves forever.
Of honorable mention is his decision in Little Lamb Village to take the Traveling mirror, which had already shown a penchant for disappearing and being hard to track down, and hide it on the only movable object in the barn.
We'd have to nominate the Midas Touch incident — mostly because by that time he'd been in the Nine Kingdoms long enough to know it ran on fairy-tale tropes, AND was warned by Wolf, who was actually native to the area, to forget it, but accepted the spell anyway, and managed to turn one of his friends to gold. Wolf later remarked, "It was almost... predictable."
He walks in on the Wolf Man angrily backing his daughter up against a wall... and just goes on with what he was going to say, apparently not even noticing.
Entire Series: No matter how elite a government agency, military unit, or terrorist organization is described as being, they will never have more than one person guarding prisoners. Usually less than one. Most often two prisoners will be left locked together in a shed filled with all kinds of useful escape tools, and a guard will check in on them once an hour. This guard will always look quite surprised to see only one prisoner left in the room when he checks in, right before being clubbed unconscious by the other prisoner hiding behind the door.
Season 1: Arch-criminal Gaines establishes his bona fides by hiring hyper-competent mercenaries, placing moles in CTU and surgically altering an assassin to get near a presidential candidate. Then he hires two incompetent stoners to kidnap the hero's daughter.
Season 1: The US Government maintains an Ultra-Top-Secret prison buried underground outside of Los Angeles. Instead of having independent power generation it is tied into the local grid.
Season 2: CTU is on high alert because of a nuclear threat. Phone repairmen show up and are allowed to wander around the building unescorted.
Season 2: CTU captures a mercenary conspirator to the plan to nuke Los Angeles. She demands full immunity for all crimes past and present in exchange for information about where to find the nuke. CTU gives it to her instead of just driving her between the most likely targets and waiting for her to save her own skin.
Season 5: Jack obtains an incriminating recording that will bring down the Big Bad. Doesn't make backup copies or phone it in to headquarters. Loses the recording. Spends a couple of episodes recovering it. Still doesn't make a backup. Gets it back to HQ safely somehow. With ten minutes to go before presenting the most important evidence he has ever collected he passes it off to a colleague and lets it out of his sight. Guess what happens.
In the Agents Of SHIELD episode "The Only Light In the Darkness", SHIELD agent Eric Koenig gets hit hard with it during his debriefing with Agent Ward. Koenig is suspicious that Ward may be an enemy HYDRA agent and draws a gun on him, and his own super-sensitive lie detector is throwing big red warnings all over the place. Even so, one adroit answer from Ward (with a liberal use of Exact Words) is enough to get Eric to trust him completely.
Agent Victoria Hand also gets a few big bounces in. She sends Coulson's people into a hostile zone with no extraction plan knowing that Coulson would go in and extract them, instead of simply asking him to do exactly that. She uses an incredibly stupid "plan"—which has the possible side effect of getting herself or her team killed—to smoke out any HYDRA agents she encounters at The Hub. And while transporting the Big Bad, she brings along his personal protege, then hands him a gun expecting him to kill his "former" mentor. Unsurprisingly, this last one made her Too Dumb to Live.
Ward himself grabs the ball in "Yes Men", when he confronts the episode's villain Lorelei, an Asgardian Seductress who can mind control men with her voice and touch. Ward manages to get the drop on her, and is equipped with a gun that will stun Lorelei but deal no permanent damage. So, the intelligent thing to do would be to shoot her before she can react and use her powers, right? Ward's even been shown to take such a policy with previous superpowered threats, but for some reason decides to try and convince Lorelei to come quietly while knowing full well the range of her powers. This gives her ample opportunity to try and seduce him with her voice, and when that fails, she merely walks up to Ward and touches him, who still doesn't try to defend himself. Coulson gets an honorable mention for sending Ward in alone knowing what Lorelei could do to him.
Wesley's actions during the latter part of Season 3 seem to consist of one-half Deathgrip on the Idiot Ball and one-half badass, stirred to taste and left to simmer. Why he a) first went to Holtz instead of, how you say, one of his own goddamned friends and b) beat the everliving crap out of Lorne when Lorne got a partial reading of him while Wesley was singing instead of continuing to sing, letting Lorne carry on reading him and figuring out just why Wesley was abducting Connor is an abiding mystery, the answers of which are known only to Angel's writers.
But Wesley does not carry the idiot ball alone there. Just as Wesley is about to walk out the door with the baby, the gang already learned most of the evil plot, yet rather than say walk in the door and say "Hey the bad guys have been feeding Angel his own son's blood, making him act crazier than usually," for no reason the whole crew remains silent on this important information, not one of them even brings it up, to Wesley, who at the time was the boss.
Are You Being Served?: It's shared around pretty equally; the characters' intelligence level can be extremely variable. However, Miss Brahms seems to get stuck with it a lot later in the series, which is odd considering she was generally quite smart earlier in the series.
Lee Adama is the usual carrier of the Idiot Ball. It's lampshaded when Roslin tells him she knows she can count on him to do the right thing, but the smart thing? Not so much.
The funny thing? He doesn't always do the right thing either. When it comes to the Cylons he's quite the Knight Templar, in fact. The true Honor Before Reason and champion of justice? Karl "Helo" Agathon. Though he has a fairly massive one of his own in "Someone to Watch Over Me", when he mistakes Boomer for Athena to the point of sleeping with her, after he's already noticed something's up with her, has been living with Athena for four years, and their deep, true love being an important plot point.
Kara Thrace also has a few of these, although the absolute king of this trope has got to be Dr. Gaius Baltar.
His crowning moment at the end of season 2 involves giving a suicidal Cylon he wants to keep alive a nuke that she didn't know existed, much less asked for. Oh, and she has religious problems with actually committing suicide, but she's been abused by humans, she's now hiding on a human ship, and dying while fighting humans seems to be no problem. The results are predictable.
Baltar pushes her to have sex with him. Only a few months after she was gang-raped and beaten repeatedly. She must have blown up the ship because being pushed into sex with her only friend finally broke her sanity.
Col. Tigh also gets hit hard by this trope. One amusing example was when, after ordering in the Marines to quell rioting in the fleet and being told that there weren't enough Marine officers to lead all of the necessary teams, he came up with the brilliant idea of assigning Viper pilots to lead the teams. You know, those guys who spend all their time flying around in Vipers and have absolutely no experience whatsoever at leading men into combat.
Cottle is usually immune, but when he gets hit, he gets hit badly: such as participating in the lie about Hera not surviving her birth. As if there wouldn't be consequences once Helo and Athena discovered the truth! It seems like he's picking up the ball again when he refuses to even listen to evidence that a colleague might be hurting a historically persecuted ethnic group, but he demonstrates some off-screen competency by actually going to check up on the patient files and autopsy on his own, coming to the conclusion that something actually is up.
Tom Zarek and Lieutenant Gaeta also get this during their attempted coup. So, they are in control of Galactica's CIC, have Admiral Adama and the humanoid Cylons in custody, but Lee and Starbuck are still at large, there are unsecured/unguarded areas of the ship, and Laura Roslin is on the Rebel Basestar (which might be beat up, but still has its weapons). So, what do they do instead of consolidating their hold on Galactica and the fleet? They spend two hours putting Adama on trial for "betraying humanity and providing aid to the enemy", taking a break to murder the entire Quorum of Twelve. At least Zarek was genre savvy enough to know that Adama was a liability as long as he was alive. Gaeta was the one who pushed to have him stand trial.
Being Human: Mitchell gets one in the episode where Tully moves in. He comes home and finds that Annie is outside, scared and crying, after Tully tried to rape her. At this point, it has begun to show that George and Tully were starting to bond over their lycanthropy, so he protests over Tully's forced eviction. Instead of Mitchell taking George aside and explaining to him what Tully tried to do to Annie, he makes out like he's simply tired of Tully being a permanent guest, which leads George to become angry (which is somewhat reasonable, since Mitchell spent the entire first part of the episode encouraging the neighbors to visit whenever and all but forced George to spend time with Tully in the hopes that it would help George deal with his condition). The result is that when Mitchell finally does think to mention the assault on Annie (as a sidenote in the argument, more or less), George is too worked up to really care. Granted it was a very icky situation and Mitchell was shown to be very protective of his friends, but still....
After the first season, Blackadder got a major upgrade and became the snarky, Genre SavvyOnly Sane Man that everyone knows and loves. This didn't stop him being handed a major Idiot Ball in the Series 2 episode "Bells", where he cannot figure out that "Bob", his manservant, is really a girl. (She doesn't make any effort to disguise her face or voice — it is obvious to every viewer from the moment Bob appears onscreen.) They have a rather sweet courtship anyway — which in itself was an Out-of-Character Moment for him.
This is particularly notable as even the writers seemed to regret it — they brought "Bob" back in Series 4 episode "Major Star" and this time Blackadder recognizes her real sex right away, and doesn't even attempt have a relationship with her. Everybody else is still fooled, but this fits perfectly with their characterization and Blackadder's status as the Only Sane Man.
Approximately one out of every three episodes is driven by the Idiot Ball. Walt in particular is frequently compelled by his own ego to go poncing about with it.
Hank's convinced that Gale must have been Heisenberg? Time for Walt to start disparaging Gale by saying he clearly wasn't the chemical genius that Heisenberg must be.
Walt has incontrovertible evidence that he knew Gale and that Gale knew him. Better leave it sitting in plain view on the toilet tank.
Walt needs methylamine, a substance that would be trivially easy for a genius-level chemist like himself to make from materials that are not on the DEA's watch list. Obviously, the way to get it is to pull a complicated train robbery.
Intentional. The writers have stated that while much of the chemistry is depicted correctly on the show, they purposely misidentified some of the key compounds so as not to be an instruction book on meth synthesis. The "methylamine" on the show was a stand-in for whatever chemical would actually be hard to buy and/or make.
One example that's actually lampshaded late in the series is Walt and Jesse continuing to use the decrepit RV well after the point where they have more than enough cash to buy a decent, working one (or at least get the old one fixed).
The entire cast in the episode "Intervention." No one wonders why Buffy's acting oddly and using highly unusual speech patterns only three episodes after a robot with identical behavior and mannerisms showed up, and everybody could immediately tell it was a robot then, despite next to zero hints.
Lampshaded in the very same episode, when Buffy herself walks in the house and comes face to face with her duplicate. The other characters are stunned and bewildered, to which Buffy (having heard all of two sentences from the Buffybot) responds:
Buffy: No, she's a robot. She acts just like that girlfriend-bot that Warren guy made. You guys couldn't tell me apart from a robot?!
The Initiative were portrayed as staggeringly stupid and incompetent, simply because the whole nature of the show required it.
And then Angel picks it up a few episodes later when he's trying to awaken Acathla. He has to torture Giles for hours to find out that he has to use his own blood for the ritual, even though the Latin part contains the phrase Sanguia Meam. Roughly translated, it means my blood. And Angel definitely understands Latin.
Also in "This Year's Girl"; after Faith has woken up from her coma, Giles and Xander are out searching for her, and try to enlist Spike's help — only for him to remind them that he hates them all, and despite his ongoing Spikeification would be more than willing to sick a rogue psycho Slayer on them. Promptly lampshaded:
Xander: We're dumb.
In "Gone," Buffy is made invisible, and goes to have kinky sex with Spike. Xander walks in, and unquestioningly accepts that Spike was doing push-ups. Note that Buffy still makes audible noises throughout the whole scene, and Xander already knows about the invisibility.
The worst in the entire series may be Xander in "Once More with Feeling". It turns out that the whole reason people are stuck acting like they're in a musical, and worse, people are literally dancing themselves to death, is because Xander found Sweet's talisman and decided that what his emotional friends needed was a demon to come to town and force everyone to sing and dance. Xander summoned a demon to make everyone happy. This is probably the worst example, because while not only is it stupid, it is entirely out of character and is painfully obvious that it happened only because the writer (Joss) needed someone to do it.
Burn Notice: If Michael Westen had just taken Tom Card's pistol out of its holster and put it in Card's hand at the beginning of "Over the Line," the whole story would have been over. Michael could have just told everyone that Card had shot and killed Tyler Grey, and was about to shoot Michael too, when Michael shot him in self-defense. It's not as though Michael doesn't know how to lie convincingly, and he certainly had plenty of time in which to plant Card's pistol. Then he could have just explained everything to the authorities, such as how Card had been working with Anson Fullerton all along, etc. Michael even lampshades it in a voice-over at the beginning of the episode, explaining how sometimes, even a veteran spy is just too shocked to be able to react quickly enough. Considering the situations that we've seen Michael keep his cool in, that seems hard to credit, though.
Charmed: The later the seasons, the more these tend to be thrown around.
Community: In the episode Physical Education Señor Chang comments on this when everybody, including Annie, forgets to check the front cover of a schoolbook to see who owned it last. (She blames Britta's pronunciation of the word "bagel" as "baggel", saying it was distracting.)
In the episode "Whataphobia", Lacey is revealed to be terrified of balloons. The rest of the episode centers around different reactions to this fear, such as Hank's misguided attempts to "cure" this fear. In fact, anything Hank does.
Hank's not really carrying the Idiot Ball so much as he's just an idiot.
CSI: The season 8 pilot gave the Idiot Ball to Sara, who should have encountered basic survival stuff at some point during her lifetime, either from a job safety kind of lecture (given how much wandering the CSIs do) or from a case involving a dead guy in the wilderness, as both San Francisco and Las Vegas have nearby places to get lost and noob hikers to get lost in them.
Defiance: Tommy, do not hand a loaded gun to a paraoid woman suffering from hallucinations that you're there to protect.
Degrassi: Alli is the reigning champion Idiot Ball holder. As Drew accurately put it, for a genius, she's not very smart. Forget all the many ways she screwed up her relationships with Johnny and Drew by doing the exact opposite of what they asked her to do, her crowning moment was when she cheated a bunch of poker players by counting cards and then proceeded to say out loud IN FRONT OF THEM that she just cheated them out of their money by counting cards!
Degrassi: The Next Generation: Every episode ever. Every. Single. One.
Barbara, a history teacher with a wide and extensive knowledge of even obscure points of the subject, completely forgets that medical treatment in the French Revolution was not as good as it is in 1960s Britain. A chunk of her plotline involves her trying to get Susan to a doctor, and she is shocked when the doctor just wants to put leeches on her.
Susan, who previously was shown to be easily scared but able to endure fear when she was forced to (see "An Unearthly Child", "The Daleks" and "The Sensorites") refuses to attempt to escape from a prison cell where she has been told she will be guillotined tomorrow, because there are rats in the cell that she is scared of. Even if that was a sensible priority for fear (even Phobias in the real world do not override known threats to life), this means she remains in the cell with the rats...
The Doctor in "The Gunfighters", in addition to being more of a Cloud Cuckoo Lander in general, forgets that frontier dentistry is Meat Grinder Surgery, refuses whiskey even to numb the pain of a tooth extraction, and refuses to believe that Doc Holiday is trying to use him as a decoy and is not actually his friend even though it's blatantly obvious.
"The Ice Warriors" generates most of its plot tension by the fact that Leader Clent is an Obstructive Bureaucrat completely dependent on his computer to tell him what to do, and refusing to either take the initiative or allow anyone else to. Multiple times the other scientists get a plan in motion only to have it scuppered by Clent's insistence on going through the computer. Dealt with realistically in that everyone else on the base hates him for this, and one has even left civilisation to become a scavenger due to how unbearable he is to work with. Also, bosses like that are Truth in Television.
"The Web of Fear" has The Social Expert the Second Doctor be completely unable to read who is and who isn't a Great Intelligence puppet. Granted, he was stressed out at the time (and an object of suspicion himself) and the actual identity of the puppet is someone very easy to overlook, but it is rather odd for a character who can usually detect liars just by looking into their eyes and read group social dynamics just by watching people when he asks a question to act with distrust towards Col. Lethbridge-Stewart.
In "The Krotons", the Doctor tells Zoe that the learning machines are being used to brainwash the Gonds and tells her not to wander off. She immediately wanders off and plugs herself into the learning machine to try it out.
In "The Brain of Morbius", the Doctor has already deduced that Solon has been lying to him, is part of a cult worshipping a Time Lord war criminal, and has a fairly creepy fixation on his head (and has tried to drug him to remove it once already). Yet when Solon says that Sarah's blinding is permanent and can only be cured by the Sisterhood, he accepts this without question and heads off to talk to the Sisterhood even though in their last encounter they'd tried to burn him alive. This also isn't a great plan from Solon's perspective, since the Sisterhood only execute people by burning them for religious reasons, a method which would have destroyed his head.
Episode "Father's Day"
A glaring example is when Rose ignores the Doctor's warning about interference and stops her father from dying, despite seeing firsthand exactly what happens when you ignore the Doctor.
The Doctor's not too clever there, either. Why would he take the girl with daddy issues to the exact point where her father died? Conversely, in his defense, he did warn her not to fuck up history when he did consent to take her there and gave her explicit instructions on what to do to avoid that, but the point that he grossly underestimated her emotional issues still stands.
The Ninth Doctor himself seems to be holding one in "The Unquiet Dead", where he urges helping the Gelth cross a space-time rift without even bothering to wonder why the corpses they have so far taken over all turned homicidal immediately. Possibly justified in that he feels responsible for the Gelth as victims of the Time War.
The Series 2 finale "Army of Ghosts/Doomsday" suffers a lot from this. When Torchwood find a way to draw energy from the void ghosts start appearing all over the world. What is Torchwood's reaction to this? Nothing, just treating it as a natural phenomenon. Within a couple of months people start thinking the ghosts are loved ones, for reasons that are never made clear. Then the Doctor closing the void and using it to suck the Daleks and Cybermen back. He decides to hold on using a metal clamp right next to the void and send Rose to the parallel world so she will be safe. However she returns and hangs on with him. Due to a lever breaking she turns it on again and ends up sucked towards the void, but her Parallel father saves her by taking her to the Parallel world. It never occurs to the Doctor to use the TARDIS, which is not sucked into the void despite having been through there, to keep safe. Or to find some way of turning on the void shift that doesn't involve them being right by the breach.
In "The Waters of Mars" the Doctor has what is intended as dramatic but in retrospect obvious realisation - the rules of time travel that he's been following for so long don't exist any more because there are no Time Lords to enforce them. The Doctor takes this as his cue to abuse time so Everybody Lives in a case where people's deaths were actually vital to the course of human history. It backfires so badly he recognizes he's gone too far, and tears up about it in "The End of Time".
Amy, Rory and the Doctor have a pretty extended Idiot Volley in the beginning of "The Girl Who Waited." First we have the Doctor and Rory forgetting the Doctor's own rule of "don't wander off" by going through an important-looking door while Amy is going back to get her phone. Then when Amy tries to follow them, all they tell her is to "press the door button," even though there are two buttons, very clearly labelled "GREEN ANCHOR" and "RED WATERFALL"... Amy then proceeds, instead of asking for clarification, to press the wrong button and step into an accelerated time stream, separated from her companions without even looking into the room first to see if she was going the right way.
"Dark Water" has the Doctor fail to notice the fact that the entire base is riddled with Cyberman iconography. He even lampshades that by complaining that he keeps feeling like he's missing something obvious.
An arguably minor one from the same episode has Missy reveal her true identity as the Master for no apparent reason, other than to make an interesting cliffhanger.
"Last Christmas" has a part where Clara is concerned about an apparently empty room, calls "Doctor?" and then heads into the room without pausing. Of course she gets attacked. This is a standard companion manoeuvre and wouldn't be notable had "Cold War" not gone out of its way to establish that Clara is the companion who doesn't wonder off.
Dollhouse: Has the entire staff hold this to create a certain plot element in the second season. In the first season near the end Alpha destroys the backup of Caroline, Echo's original persona and steals the main copy of her, which is retrieved. In season two they opt to bring her back, only to find the main copy is now missing. So that leaves them with only the smashed backup that needs to be reassembled. Creates a plot element there, until you wonder why they didn't make yet another backup of the original copy with the backup effectively destroyed. Keep in mind that there is a timespan of approximately a year between these two events.
The Drew Carey Show: Lampshades and inverts this by having the characters pick up an object called an Epiphany Ball while snooping around in a laboratory at night. Whoever holds the ball suddenly gains understanding to all their problems. Predictably, after it gets passed around a bit, they fight over the ball and it is shattered as it dropped to the floor.
Everybody Loves Raymond: In one episode, Raymond and Debra have both sustained injuries after falling out of bed during sex. To avoid admitting this to Marie, they make up a lie about falling down the stairs. For some reason, Marie is skeptical that they both fell at the same time. The obvious answer would be that they were both going down the stairs, one of them tripped and knocked the other down with them; however Debra instead makes up the ridiculous notion that they were having a race, as part of a "weekly tradition". This is a surprising lapse in judgement considering she's usually portrayed as the brains of their relationship.
Falling Skies: Has a few in just one episode. Tom tells us a few times that Pope is a really bad guy, so when they take him to find motorbikes he's guarded by Dai. Dai and Pope end up in a back of the bike shop and for some reason Dai turns his back on Pope and looks for something. Pope then knocks him out and flees from the group. In the same bike shop one of the skitters wall crawls his way to an advantageous spot above Tom and Dai who are completely focused on escape from the child soldiers, so what does it do? It jumps on the desk below it, makes a bunch of noise and gets filled with lead.
Friends: Every now and then, a character would usually have to pick this bad boy up and run it into the endzone for a off-kilter subplot to work. Some of these, though, were probably just Played for Laughs.
Or when Joey was trying to learn French from Phoebe, but couldn't even repeat simple words, instead spouting a stream of pure gibberish.
Monica and Chandler frequently grabbed this when they first started going out. There were countless times where they almost got caught. While it is partly justified in how it would be difficult to keep a relationship like that a secret in such a tight-knit group, they were really careless most of the time. Such as having sex against an open window after Ross decided to check out and live in the apartment opposite. Twice. The rest of the cast besides Joey (who figured it out first and by putting 2 and 2 together rather than either hearing or seeing them in the act) grab the ball since they took about 6 months to figure it out.
In "The One With Ross's Sandwich", Joey is forced to help cover up Monica and Chandler's affair. None of the gang seems to figure out that anything's wrong, even when it makes no sense, such as when Joey claims what is actually Chandler's underwear in Monica's couch. Or when Joey finds a naked picture that Chandler took of Monica.
Also the one where Chandler believes Monica wants plastic surgery.
Plots in the last couple of seasons increasingly relied in characters holding the Idiot Ball.
Ross and Rachel spent ten years playing Idiot Ball hot potato.
Fringe: Peter is meant to be a genius, with an insanely high IQ and perception enough to realize that he's from another universe. He's also known Olivia for over 2 years now. At the end of last season, he and Olivia finally admitted their feelings, to some extent anyway. Then the two Olivias, the one from the parallel world and the one from our world, switched, and he somehow hasn't noticed even though a) he's noticed how different she is, b) he's surrounded by cases of imposters from Over There, and c) he's spending so much time with her that they've slept together. Even Peter's actor admits he's gotten the Idiot Ball this season. When a reckoning came around, Olivia chewed him out for it, and their relationship was somewhat rocky thereafter, until they finally go together.
One notable incident occurs when Peter has spent several episodes attempting to retrieve a box while suffering amnesia. He gets it open and finds his driver's license, and then complains that knowing his name doesn't help him know who he is. A simple Google Search for "Peter Petrelli" who happens to be the brother of a political candidate would have cleared up much of Volume 2.
There was also the part in volume two where Peter teams up with Adam Monroe to destroy a deadly virus that can kill 90%+ of the world's population. Of course, Adam is really planning on releasing the virus. Several people along the way, including Hiro, tell Peter than Adam is evil and Peter refuses to listen until Nathan intervenes. Now, the justification is that Peter owes Nathan's life to Adam and has become The Dragon. But Peter has the ability to read minds, and could have easily read Adam's mind to confirm if he was a bad guy or not? Peter even uses his mind-reading on a woman named Victoria while she's trying to tell Peter that Adam is bad news so it's not like the writers forgot Peter had this ability.
The most infuriating examples would have to be Elle, Nathan, Mohinder and (to a lesser extent) Tracy during the third season. All four characters would switch back and forth between being good guys and bad guys at the drop of a dime with no real motivation ever given for any of their actions leading to some pretty stupid decision-making. Elle became such a nonsensical mess that it was actually a relief to finally see her get written out.
Hogan's Heroes: Had a good deal of this for Those Wacky Nazis (which may have been the whole idea, of course; Colonel Klink and Sergent Shultz were supposed to be incompetent), but occasionally for the good guys.
Every so often, House or one of his team will miss something ridiculously obvious so the plot can be padded out to 42 minutes:
Despite stating regularly that "Everyone lies", it rarely occurs to the team that asking somebody if they've slept around is unlikely to elicit the truth, even more so when they're asking a child in the presence of their parents. It's not like House wouldn't happily lie (eg. "Sorry, there seems to be a problem with your insurance - we need you to go down to accounts to clear it up, we can't do anything until it's sorted out") to get them away from whoever they might want to keep a secret from.
"Maternity" — Every doctor at Princeton Plainsboro managed to conveniently forget that newborns carry the same antibodies as their mothers.
Admittedly kinda silly, but they were more concerned with dying babies and they were only stumped for a short time before the "Oh that's right!" moment
"Histories" — Foreman didn't make a connection between the bats he found at a homeless patients shelter and rabies.
"Distractions" — Every doctor failed to notice the cigarette burn and nicotine stains on the patient.
"Skin Deep" — Every doctor managed to miss the fact that their patient had no uterus and didn't notice the pair of undecended testes in "her" abdomen despite numerous ultrasounds and scans.
She only had the one ultrasound as far as I can recall - Wilson mucked it up thinking her ovaries were simply undersized and wouldn't be looking for a uterus when he was searching for ovarian cancer. When they got a proper scan, that's when the problem reared its ugly head
A lack of uterus is a pretty big thing to miss in an ultrasound, even if you aren't specifically looking for it. That would be like looking at a chest x-ray to see if your patient has lung cancer and not noticing that he doesn't have ribs.
Foreman fired Thirteen, because her working as his subordinate would break them up. There is no way she would dump you after that, genius! Say it with me.
There's also no way your female boss would have any problem with the fact that one of your first official acts as a manager was to open the hospital up for a crippliing sexual harassment lawsuit by telling a female subordinate that you're firing her specifically so she'll have sex with you.
Also applies for at least 50% of the patients... as an example, the parents who didn't mention that their son was adopted (thus invalidating his medical history) because "he didn't need to know."
To be fair, they did give his birth mother's medical history instead of theirs - they just didn't mention that it wasn't theirs.
In "The Itch" Cameron carries an Idiot Ball the size of a house. She keeps making idiotic decisions to keep the shut-in patient at his house (or at one point BACK to his house), because if they got him to the hospital they could give him a real test and the episode would be over.
This happens in House almost every episode, and a huge number of their cases would have been incredibly brief had they done simple things (like the standard physical examination every doctor three seconds into med school knows to give), things they do regularly (if they don't administer antibiotics early on you know it's an infection) or things that should be on their mind (last week we ruled out an obscure disease because we couldn't find the rash it presents with, maybe we should be more thorough on our exams in the future).
I.e. the time they thought a patient had a tick but couldn't find it any where on they visible body, so they tested for other things... never thinking that maybe the tick was on the non-visible part of the body like underneath his thick head of hair.
That's an episode of Scrubs. In the episode of House where a patient had a tick, it was hiding inside her labia. It's partially understandable why they couldn't find it; genital exams are rarely required when searching for ticks.
Jerome and Joy both get one, when they are kept in the gatehouse, along with Patricia and Alfie, to do an 'extra credit' project for their teacher, based around an eclipse coming up. Patricia and Alfie are aware that it's really ceremony to awaken Robert Frobisher-Smythe. Jerome and Joy, however, refuse to believe them. This wouldn't be so bad... except Jerome and Joy both dealt with the mysteries in both of the past two seasons. Heck, Joy had even been part of Sibuna in the beginning of that very season, and Patricia and Alfie are their best friends. Neither of them had any reason not to believe Patricia and Alfie.
Later KT gets a minor idiot ball. In an effort to convince her that Fabian was turned into a sinner, Alfie mentioned that he had talked to Joy, who was crying in the hallway after Fabian verbally trashed her. KT argued that she saw Fabian and Joy and Fabian didn't even say anything. The problem is, Alfie wasn't there with her- so how would he have known about Fabian and Joy, unless Joy told him herself? She also tried to go visit the gatehouse in the middle of the night for... some reason... without telling anyone she was going. Of course, she was nearly captured by Robert.
Fabian is not immune either. Robert was lying on the floor of his bedroom, looking weak and begging for help. Rather than let the guy who he KNOWS is evil just rot, he decided to help. Fabian was then taken to the gatehouse, and Robert claimed he wanted Fabian to help lift a curse and take over his research when he died. Fabian, of course, accepted, and even WENT TO THE TANK ROOM WITH HIM. Gosh Fabian, you were always gullible, but... really?
Sibuna in general seem to fall prey to this. How many times will they talk loudly about their plans in the hall, or allow themselves to get tricked by the villains? A lot, apparently.
One episode revolves around this. Robin and Lily spend the episode on a chase around New York to find Ted, who has (according to the stories of the people they ask) been apparently cheating on Robin and generally doing things that really "don't sound like Ted". It later turns out it was Barney the whole time, who gave Ted's name to prove that the line "Ted Mosby, architect" makes girls want you. If only either of the girls had thought to ask any of these people what Ted looks like or what he was wearing... I guess hearing "blonde" or "in a suit" would have killed the entire episode's plot in five minutes.
This trope appears where a string of increasingly hand-bangingly moronic decisions on the part of Marshall and Lily ends with them buying an apartment they don't need to own located near a sewage plant they never bothered to find out about with a slanted floor they never inspected for and a mortgage they can't afford due to debt they could have avoided. Future!Ted, narrating from the year 2030 and gifted with 20/20 hindsight, lampshades every idiotic decision by showing them saying something level-headed and mature, interjecting with "... is what he/she/we SHOULD have said", and then showing the stupid thing they actually did. Basically, a cautionary tale to his kids showing them how even people who should know better do really stupid things sometimes, so that they won't repeat their Aunt and Uncle's mistakes.
When Marshall shaves a streak of his hair on his wedding day, Ted and Barney come up with many ideas to make the situation better because they honestly don't know what to do. Barney even suggests wearing a Native American (AKA American Indian) headdress which is close to the real, and simple, solution that Lilly comes up with. Just wear a hat.
Marshall: "Hat." We thought of "authentic Native American headdress" before we thought of "hat".
I Carly: All of them. Spencer is especially prone, as he can switch between intelligent protective older brother into someone who will build a machine seemingly intended to fling hammers at high velocity at head height, or a "sculpture" which seems tailor-made to catch fire at random.
I Dream of Jeannie: Major Anthony Nelson constantly waves off Jeannie's amorous advances despite her being rich, having MAGICAL POWERS, and also being more beautiful than his usual dates. (In Tony's defense, Jeannie's efforts to please him did tend to get him into trouble numerous times, giving him a somewhat-valid reason to be cautious.) He did finally get around to marrying her in the sixth season.
JAG: In the season 5 episode "Drop Zone" Mac grabs hold. She is prosecuting a Navy SEAL for causing deaths and injuries of some of his trainees in a jump exercise. When she leaves the office, in her car she found a medical report about the defendant, including his admission he was taking drugs during the time of the mission, and so guilty. She shouldn't have this as it was meant to remain between doctor and patient. Using her legal knowledge, she doesn't call the police to dust for prints nor the judge to inform him. She kept it and then burned it, but was still found out for merely possessing it by the defense attorney Lt. Singer. As a result, Mac nearly loses her career for her actions.
Lt. Singer did not "find out" Mac had seen the report; she (Lt. Singer) PLANTED the report in Mac's car in order to sabotage her ability to do her job; and then she engineers a chain of events in court that force Mac to admit that she had seen the report. You are correct that Mac could have handled the situation better than she did, but as it is, she did all she could to continue arguing her case without using any information she gained illicitly.
Kamen Rider Blade: The final storyline dealt with trying to stop the Joker from winning the Battle Fight and causing The End of the World as We Know Itthe problem being they don't want to seal him because he's become a human and friend. Tachibana suggests unsealing the Human Undead and then sealing the other two, but no one wants to seal Joker still, leading to him being the winner and Blade having to turn into another Joker to Take a Third Option and save both. Alright, fair enough. Except for the fact Kamen Rider Leangle has the power to unseal Undead and they've got the Tarantula Undead, whose a very nice guy who had no intent of doing anything wrong and they spent a storyline trying to prevent from being sealed. If they'd just unsealed him before sealing the Catagory King of Diamonds Undead, then the entire final storyline wouldn't have happened in the first place! Leangle even attempts this after Joker wins but the Undead can no longer be unsealed by then, but nothing was stopping him before!
The detectives often show abysmal timing in escorting their jittery, easily disturbed witnesses out of the building at the exact same time through the exact same door the violent rapist/abusive boyfriend/evil family member is being brought in.
Subverted Trope in the episode "Savant" in which the crucial witness in a brutal assault is a little girl who can recognize any voice she's heard. She manages to identify the boy who put her mom in a coma when she hears his voice as he's walking by to collect his dad, who was previously the main suspect.
Robbie Rotten has one goal and one goal only: Get rid of Sportacus and return the town to its original lazy state. So when he gets his hands on a genie's lamp, what doesn't he wish for? Sportacus to disappear!
Admittedly, Robbie eventually did use his final wish to get rid of Sportacus, but by that point, the genie was so sick of him he got rid of Robbie instead!
In "The Award", Mary takes a lot of character derailment and sets in motion a chain of events that make you question her sanity and sense of reason. The plot can only take place because Mary acts like a complete idiot.
In "The Good Shepherd", Pa and Laura act like complete idiots. Pa goes on and on about his new son so much that Laura feels inferior, refuses to pray for the baby, and runs away. Laura's resentment for the baby had been building for a year and a half and it was never noticed by Pa; moreover, Laura, who is usually outspoken and very close to her father, never says a word to him about it.
In "The Monster of Walnut Grove", Laura sees Mr. Oleson chop the head off of a mannequin. She runs home and tells Pa that Mr. Oleson killed his wife. Pa grabs the idiot ball when he tells her it was just her imagination and leaves it at that. This is necessary for the plot of the story, but out of character for Pa.
In "The Runaway Caboose", Willie Oleson trades Carl Edwards some fireworks for an aggie. Carl decides to set them off in a barn.
Have any of the losties ever asked the Others the rather relevant question: "Why?"
It would help. How much, we won't know, considering how the Others are cryptic (and in the case of Ben, outright liars) in their conversations.
The whole "Nuke the Swan" plot line in the last few episodes of Season 5. The A-Team are convinced that setting off the nuke will prevent the Incident. Ten minutes before they're going to do it, the resident Deadpan Snarker Miles asks if they ever considered that the nuke might cause the Incident. The silence leads to Miles to mentally facepalm and say, "I'm glad you all thought this through." And by the way, it does.
Ilana had been training all her life for her mission and probably knew everything about the candidates (such as the fact that they can't kill each other or themselves). So in "Everybody Loves Hugo" she not only handles dynamite herself for no reason, but handles it more carelessly than Arzt and dies because of it.
In the pilot, some of the survivors find the plane's cockpit and the pilot still alive inside. Then they are attacked by what is obviously a very large, powerful animal which tosses the cockpit around like a chew toy. So what does the pilot do? He sticks his head and shoulders out of the broken cockpit window in order to try and see what it is. Is anyone even remotely surprised that he is promptly hauled out of the cockpit headfirst and eaten?
Policeman: So you found the gun, removed it from the original holder, touched it again to move it to a different spot, used a hacksaw to try to disable it and shot it, and didn't think to call the police until after that? Malcolm: Yeah. Policeman: What's your IQ again?
Actually Malcolm, despite his high IQ, has had many Idiot Ball episodes, especially in the later seasons. Though these actions seem to stem from the belief It's All About Me.
The Mentalist: Way to go, Jane. It's a brilliant idea to break into a suspect's house to get proof he's a hitman. Jane would have gotten away with it if he hadn't made himself a cup of tea and left his fingerprints and DNA on the cup. Shockingly, the suspect was released.
The main character kick-starts an episode's plot by conjuring the smoke of a camp-fire into the image of a galloping horse. A woman sees it, tells King Uther, and a witch-hunt begins. Merlin spends the remainder of the episode lamenting just how stupid he was.
And in another when Morgana has gone to see the Druids for advice, Uther thinks she has been kidnapped and so Merlin has the bright idea to cause a big commotion escaping the locked up city (as opposed to trying to sneak out quietly) and for no reason at all lights a fire in the middle of the forest thus leading the knights right on his tail to where the Druids are hiding.
Gwaine and Guinevere had a moment of brilliance immediately followed by a moment of incompetence in the series finale. In an unexpectedly Genre Savvy move for the good guys, they manage to figure out that Gwaine's new crush is actually a spy working for Morgana. They give her false information about the whereabouts of King Arthur, and then arrest her once she's sent it to Morgana. Then it occurs to them that they have a golden opportunity to strike at Morgana when she attempts to follow up on the false lead. But rather than sending a few hundred men to deal with her, Gwaine decides to go after her alone, taking only one other knight (Percival) with him to battle a known sorceress and Camelot's most dangerous foe. This, of course, backfires, as Morgana easily defeats the two men, uses magic to force Arthur's true location out of them, and then kills Gwaine.
Naeturvaktin: the two employees miss several obvious opportunities to get Georg, their bullying boss, fired. Instead, they grab the idiot ball at the crucial moments so the series can run to its conclusion.
NUMB3RS: The entire FBI hauls around an idiot ball the size of the shop. While for the sake of the plot it's all right that every case they meet requires advanced math to solve, it does not explain why the FBI is incapable of any police work. One of the more outrageous example concerns a fugitive whom the FBI has been after for months. They know the man is on the run, but has not left his home county. Even with that they still cannot find him, but even worse is the fact that the show's resident math genius uses advanced math to reveal to the FBI that the fugitive is regularly stopping at his old home to visit his wife. Indeed, at no point in those long months has it ever occurred to any of the FBI's agents that the fugitive who's staying in his home county may be contacting his loved ones and that they could just catch him by putting up surveillance on the man's wife. The whole show is like this, featuring FBI agents whose only qualifications are that they are damn good at kicking down doors while shouting for people to drop their weapons.
The Office: In season 6, Jim takes the Idiot Ball and runs with it. Jim is often the voice of reason, or at least the one able to point out when someone is being foolish. However, when he accepts a management job he suddenly becomes irrational and does stupid things like sharing management responsibilities with Michael and giving an unfair raise to the sales staff. Why he suddenly becomes an idiot after six years of relative sanity is unclear.
In the second season, Emma shoots her gun to break up an argument. After learning that ogres hunt by sound.
Not to mention Emma telling Cora about Henry.
And from the same episode, Snow drinks "water" from King George, a man who would love to dole out revenge on her.
Henry has to make a decision. On one side is his adoptive mom and his bio mom (who NEVER see eye to eye) and the other side is this guy he just met. He chooses poorly and IMMEDIATELY regrets it. ( The strange kid wound up being the big bad for the first half of Season 3).
In the second half of Season 3, Snow White picks a total stranger to act as her midwife. She winds up being the Wicked Witch.
Belle and Neal trust a man trapped in a candle about how to revive Rumpelstiltskin. Belle clearly seems to have doubts, immediately questioning the candle about why she's never met him before and accepts his simple answer, so she and Neal go on a trek to accomplish their goal. Even when they learn that Lumiere is lying, Neal stupidly revives his father, which costs him his life, subverting his goal of being with Emma and Henry again, and gives control of the Dark One to the Wicked Witch. It's made worse by the fact that Neal has spent his life being wary of magic and understanding it comes with a price. Yet, for apparently no reason he forgets all this to revive Rumpelstiltskin. Love for his father and family aside, Neal clearly knows better than to mess with dark magic. This plot seems to arise because the writers have pulled an Idiot Ball in forgetting Neal's reasons for leaving the Enchanted Forest simply to create a Conflict Ball later.
Generally an Inverted Trope. During every sketch, one of the idiotic policemen seems to be handed the Smart Ball, demonstrating an inconsistent amount of skill and intuition in dealing with the idiot criminal or idiot partner. This could be Hand Waved by the necessity of the comedic Straight Man.
The Smart Ball seemed to go to all the bit-characters, making them practically Mary Sue perfect in order to make the regular actors look idiotic... and more annoyingly than ordinary Mary Sue characters, since it would usually end up with the regular characters being injured or humiliated in some way, but they were also center-stage while the bit-characters were barely visible.
In episode 4, when a storm drops a huge pile of rubble on Captain Neville, Danny has the perfect chance to escape, and let a dangling stove kill him... so naturally, he turns around and digs him out. He actually seems surprised about being handcuffed... He was reluctant to save Neville, so it's more of a case of Honor Before Reason.
Captain Tom Neville in episode 5. He has Danny sitting in a chair, and he thinks it's a good idea to not tie him to the chair and to turn his back on him. And this is after Danny has openly shown himself to be a Crouching Moron, Hidden Badass, The Dog Bites Back, and showing a refusal to be intimidated or impressed by Neville, and just giving him Shut Up, Hannibal! responses.
Charlie runs with it in "Sex and Drugs" when she agrees to assassinate O'Halloran for Drexler in exchange for saving Nora. She learns that unlike The Sociopath drug lord Drexler, O'Halloran is a former police officer and family man—and yet attempts to go through with the plan anyway. Yes, Charlie, kill off a potential ally who has a strong enough force at his disposal to destroy Drexler's fields, rather than have him help to destroy Drexler's operation and save your friends.
The title character. After assembling his Merry Men, he has Will Scarlett craft the team their own small wooden "army tags" that are inscribed with a bow and arrow and worn around their necks. This is silly enough, but then Robin breaks into Nottingham Castle andshowsone of these tags to the Sheriff, informing him that anyone wearing one of them is in Robin's gang.Buh? Sure enough, a few episodes later the Sheriff captures some men who are wearing these identification tags and duly has them executed an hour before Robin's rescue attempt. Seriously, what on earth was Robin thinking?
While it does have adverse consequences, this actually lines up with Robin's wisdom and character. They had just been unjustly accused of killing a nun and a child (and targeting the Sheriff) and were dealing with a huge PR problem because of it. This made it a matter of ego and necessity. It was also noble, given the Sheriff tended to assume anyone in Robin's remote vicinity was part of his gang and immediately sentence them to death. Also, Robin was never shown giving the tags to the men who were captured and killed for wearing them four episodes later. It is much more likely that Alan-a-Dale's brother and his band of thieves stole them along with the clothes, money, and horses, since the scene immediately following their betrayal is the first time you see them proudly wearing the tags. Robin specifically withheld them earlier, explaining they would need to be earned, since it was a matter of not only his reputation, but their safety.
Sanctuary: In the episode "Metamorphosis", Henry has Will pull a dangerous stunt (that does not end well) in order to change a light bulb on a chandelier that is out of reach. Nevermind that Henry is a technical genius, or that he has lived inside the Sanctuary for most of his life and should therefore know about the switch that lowers the chandelier. Even a simple folding ladder would have worked.
The Sarah Jane Adventures: Sarah Jane Smith in the story The Temptation of Sarah Jane, and her temptation to stop her parents' death, with numerous lampshade hangings. Thankfully, she's a good actor, and it's built up (she is also Genre Savvy enough to know how screwed she is).
Quinn, when she dated a reporter that she got to know when he wanted information that she had. Her surprise after he died that he was still working on the case was especially baffling for someone who apparently has so many secrets herself.
Speaking of him, Gideon was hit with his BIG time in episode 6 - When confronting the person behind the majority of the shadiness in the story you're investigating, it's always best to do so in a public place or even to not let them know all that you know. But should you do both of these things DON'T TURN YOUR BACK TO THEM! It can only end one way.
Quinn has been getting the ball a lot lately. Towards the end of season 3, she thinks nothing of it when Charlie, who is known to her as an assassin and former member of B6-13, just starts showing up wherever she is, teaching her how to shoot and showing signs of attraction to her. Then apparently she's so besotted with him that when Charlie tells her that a syringe is filled with just enough m99 to knock someone out, she jumps out of the car to inject the target herself - without asking any questions about who it is or checking for surveillance camera. This is someone who's nickname is "Baby Huck" because of her affinity for hacking into surveillance tapes and has helped the team clean up dead bodies, not to mention the very same Quinn who a few episodes ago was yelling at Olivia for not giving them enough information on their cases!
Also towards the end of season 3: It's also surprising that Pope & Associates never suspected that Candy, Congresswoman Josie Marcus's younger sister, was responsible for the computer laptop magically showing up at Senator Reston's campaign headquarters. They've seen things like it in the past and Candy was way too smug and excited when she was normally a very cautious person.
Scrubs: One episode in season 6 has Turk hurt his hands due to playing with a ceiling fan. That on its own wouldn't be too bad, except multiple episodes beforehand (even one in the same season) had Turk stress that his hands were incredibly important since he was a surgeon and that he couldn't risk damaging them. At one point, he gets pissed that JD tried to ambush him with a tennis ball. The writers made Turk an idiot with that ceiling fan in order to allow the plot to happen.
There are many specific examples, most of which are listed under Idiot Plot. There is, however, one very general one: Any time someone is spying on Clark, expect him to suddenly start talking about how his only weakness is meteor rocks. Not kryptonite, meteor rocks. That way the Monster of the Week knows what he's talking about, and can use it against him.
When Chloe went out of her way to tell Tess that red kryptonite, for lack of a better phrase, makes Clark evil. Chloe is lucky that not long after Tess underwent a Heel–Face Turn, because who knows what she could've done with information like that.
Spooks: It was sometimes held by Adam. Dies while holding it because he does a handbrake turn in a bomb-rigged car and then parks it instead of jumping out and letting it run for another twenty/thirty yards.
in addition to Juice carrying the idiot ball for most of the series (as plot demands), almost the entire last half of the finale for season 6 has almost every character carrying the idiot ball all so the conclusion can happen the way it does. If even one of the characters involved in not informing Jemma of the full decision of the MC had informed her of what was going on, then it would not have gone down that way and things would have turned out okay... as much as they can be in this show. Instead, every character held the idiot ball long enough to somehow forget that Jemma is the most hot headed and impulsive woman on the planet and would somehow not do some kind of violence against Tara. This despite an entire season (plus the rest of the show) proving that she would do exactly that. Really dumb
The death of Carson Beckett. Exactly when did walking slowly away from a BOMB DISPOSAL UNIT taking care of a high-explosive tumour nobody's ever handled before seem like a good idea?
McKay and Daniel Jackson got it in Season Five's "First Contact". If any other member of the cast had been held at gunpoint by aliens demanding that they activate an unknown device which had originally been shut down due to "unforeseen consequences" great enough that it was worth letting the Wraith live, they would have taken the bullet first. You can hand the ball to the Ancients as well, for not sending around an email saying "don't use any Stargates for the next month or so while we go pick off our stranded enemies" before switching the device on.
Michael and his Hybrids are suddenly afflicted by this in their final appearance in 5.14 "Prodigal" to make the All Your Base Are Belong to Us plot last long enough, because Michael technically already wins in the opening. This overlaps with a Villain Ball because Michael stretches out their take-over specifically so he can activate the self-destruct. The mistakes they make are still legion:
Not leaving Teyla unconscious until they're clear of Atlantis by stunning her repeatedly or even restraining her while she's awake so she can't, say, take her mission-critical baby and flee from your grasp at the first opportunity.
Leaving all the gate room people, two dozen or so stunned humans (including The Big Guy Ronon), in an unmonitored room with an accessible door panel and a single guard posted at the other side of the door. The Hybrids could have just killed them all to save themselves the trouble of bothering to seclude them after they've been knocked unconscious. They were already planning on blowing up Atlantis anyway, so they had no believable reason to keep them alive beyond plot-required stupidity.
In Stargate Atlantis "Sanctuary", every member of Shepard's team has the Idiot Ball with the exception of McKay, who is ignored and castigated throughout the episode. Even Dr. Weir is holding the Idiot Ball in this one, as she, just like Shepard, Teyla, Ford and everyone but McKay, ignore what is before them, from the obvious lies and contradictions in the initial story told by the Ancient, to an Ancient lying through her teeth throughout the episode, to an Ancient allowing and facilitating her own worship as a false goddess. It was frustrating for the audience to sit through what amounted to a 42 minute group of Idiot Balls, wondering why they didn't see what was before them and wondering why McKay, of all the characters, was the only one who was actually seeing clearly.
It didn't help that the 'Previously on Stargate Atlantis' segment mentioned ascension - thereby giving away the plot before the opening credits.
The entire SGC and International Oversight Advisory are fighting over the ball in the series finale. Instead of recognizing that a structure that predates humanity (the Ancient Outpost) can't possibly be covered by the Antarctic Treaty, they remove its control chair to an Area 51 warehouse with no air defenses. Guess what the Wraith use a couple Darts for.
There's an especially wacky example in the late episode "Bad Guys". Several members of the cast, Michael Shanks in particular, have expressed their disgust with the idiocy of that episode.
The heroes go through a gate and find themselves trapped in a museum storage area with a loud party in the next room. They think they can hide six hours until rescue arrives, but then a lady shows up, screams, and runs away. Col. Mitchell's response? He chases her, rifle drawn, into the room where the party's taking place. When a security guard quite reasonably opens fire, Mitchell shoots him in the leg and takes the entire party hostage. The kicker is that Ben Browder, Mitchell's actor, cowrote the episode.
Mitchell has proven that recklessness is an established part of his character. It was actually Maj. Gen. Landry who was handed the Idiot Ball when he made Mitchell the leader of the team. Carter had her flaws, but at least she seemed to think before she acted, and Mitchell's youth makes you think that he was promoted immediately after his injury, which makes it quite likely her silver oak leaves were older than his. Go figure. And it could be argued that Carter had more than earned the leadership spot.
In SG-1's first season, there's also "Hathor".
What's known about the Goa'uld so far? They masqueraded as Egyptian deities, all known examples were among the bad guys and they wield several strong close-ranged powers, including, but probably not limited to, energy blasts, stunning and persuasion. A woman appears outside the Stargate base and identifies herself as the Egyptian deity Hathor. Hey! Why not put her into a room with the senior command staff of the base? Surely no harm will come of that, right?
That episode is has since officiallybecomenon-canon. Which brings up a major problem: we see Hathor again in two more episodes, carrying on after the episode that is no longer "canon." She even directly references the events of this episode; talking about how SG-1 have become immune to the sexual organism she used and showing flashback footage.
In the beginning of the SG-1 episode "Forever in a Day", several cast members pass around the Idiot Ball in order to contrive the circumstances that result in Sha're's death. First, the SG teams are pinned down by an ambush of superior numbers just behind the nearest hillside, leaving Daniel to wander into Sha're/Amounet's tent alone, armed with a pistol rather than a zat'nik'tel. Unwilling to kill Sha're, he is almost killed by her ribbon device when Teal'c enters the tent at the last moment, also carrying only a lethal staff weapon. And at that range, even with the inaccurate, short-ranged staff, he could have shot her in the arm instead.
In the last half of the episode "Rite of Passage", the entire cast held the Idiot Ball together in order to create a moral division, which was actually a false dilemma. Daniel might forget it, but O'Neill, Hammond, Carter and Teal'c would certainly remember that firstly, they were under absolutely no moral or other obligation to keep their word to the bad guy of the week, who was responsible for various genocides, and if they were, the Pentagon would never allow it. Still, they could have had it both ways. The ultimate aim for this was so that Doc Frasier could lose patience and save the day. But it did the rest of the pragmatic-at-heart members of the cast a terrible injustice.
In the episode "Gemini", Carter is handed the Idiot Ball so that she'd fall for Repli Carter's Reverse Psychology and lets the walking security breach access her brain and the computers at the Alpha Site.
Several episodes have untrained persons taking the weapons of SG-1 persons without difficulty. I ask: what is a trained soldier in unknown or enemy territory going to do when someone tries to take their gun?
Several episodes have SG-1 personnel being snuck up on and knocked out. While O'Neill appears to be partly deaf, the rest of the team would hear the approaching person's footsteps in gravel, dirt, brush, rocks, etc.
Stargate Universe: In the season finale, there's a particularly annoying example when the main cast is faced with the possibility of the Lucian Alliance boarding the ship and taking it over. Col. Young's plan is to suck the air out of the gate room after the Lucian Alliance gates through; the problem is that Rush-in-Telford's-body shows up with them. Now despite the fact that he just drained the air out of the cabin where he was holding Telford in Rush's body, and then revived him, he chooses to not drain the air out of the gate room altogether.
Or for that matter, simply drain MOST of the air out of the gate room. Hypoxia won't kill very quickly, but it'll certainly prevent anyone from being in a condition to fight. You'd think that this is something anyone living and working IN SPACE would know about.
One early episode has Bashir interrupt an attempt to kidnap Dax. Instead of calling security, he rushes in by himself. Then, when one of the kidnappers turns out to be a woman, he hesitates to hit her and gets promptly beaten up.
In the episode "Hatchery", the entire crew of the Enterprise is playing a 40 minute game of Idiot Ball. The captain gets exposed to a biological alien substance and shortly after starts acting strange. He soon has anyone who tries to reason with him confined to their room and starts to become completely delusional. When things get worse Tucker and Phlox talk about relieving him off duty on medical grounds, but don't go through with it because they can't force the captain to get an examination without having proof he's sick! Then the senior officers agree to start a mutiny and ambush the teams of soldiers stationed all over the ship, because they don't trust Major Hayes, who's in charge of the soldiers, to believe them that the captain is acting very strange. At the end of the episode, Hayes even points it out to them, why they hadn't just told him what's going on.
Starfleet itself has this. The Enterprise is supposed to be their first emissary out into the galaxy. While it can't be expected to go perfectly, Starfleet seems to simply not even try in many cases. When the Enterprise initiates first contact with a new species? Captain Archer just kind of says whatever comes to mind. When they discover a new Earth-like planet to explore? The crew decides to go camping on it, without doing even basic things such as, oh I don't know... checking to see if the air is safe to breath. And the camping is ALL they do. Not even lip-service to science teams going down to do research while the main characters take some shore leave.
The Xindi believe that humans are going to destroy their people in the future, so they build a Planet Buster to destroy Earth before that happens. They've got their working prototype, and decide to give it its first test run. Not by using it on some uninhabited planet, but by attacking Earth. Who were never aware that the Xindi existed, or that they were planning on destroying the planet.
The episode "Unification part 2." So, the villainous Romulan Sela has revealed her plan to invade and occupy Vulcan, but it's critical that Starfleet not be warned ahead of time. Across from her is seated Captain Jean Luc Picard, Lt. Commander Data, and Ambassador fuckin' Spock-three of the smartest and most bad ass characters in all of Star Trek - whom she has managed to capture. So what does she do now? Leave the three of them in her office. Unattended. And with access to her computer. Geez, it's like she wasn't even trying.
Sela also held an idiot ball in "Redemption Part 2." where she was supplying the House of Duras during the Klingon Civil War. The Federation decided to make an anti-cloak net by having some Applied Phlebotinum beams between a fleet of ships, resulting in a standoff. Not once does Sela or the crew of any of the other ships think that maybe, since Space is big and all, that she could just fly AROUND the net.
There's also Tasha Yar in "Datalore". The rest of the crew didn't do much better, but special mention must go to the chief of security for failing to recognize that a perfect twin of the second officer might possibly represent a security risk.
Then there's Deanna Troi in "Disaster". Regardless of whether you like or dislike the character, one has to admit that for a Starfleet lieutenant commander to have to be told what happens when the warp core breaches (answer: the ship explodes!) is sheer idiot ball.
Captain Picard takes the lead in "Descent". Desperate to find Data and the Borg he orders most of the crew to a planet to look for them leaving a skeleton crew led by Crusher, and apparently mostly consisting of ensigns, to look after the ship. Most people, when deciding how to split their resources, would go with using their highly experienced officers to operate the ship; leaving wandering about looking behind bushes to the lesser lights.
It was Riker's turn to hold the Idiot Ball in "Samaritan Snare." Riker sends LaForge over to a Pakled ship (the crew of which seems exceptionally slow) to do some requested repairs. Worf objects to sending them the Enterprise's chief engineer, but Riker blows it off. Troi tells him directly that she's suspicious and feels that LaForge is in danger. Riker blows if off again. Then Geordi gets captured because Worf and Troi were right and Riker ignored them. Scriptwriter Dennis Russell Bailey, who wrote the screenplay for "Tin Man" in the following season said, "The point at which we became serious about trying to write a script for the show was about five minutes after watching 'Samaritan Snare,' which in my personal opinion was the most abysmal piece of Star Trek ever filmed. My objections to it were that it always resorted to idiot plotting to make the story work, and that offended me a great deal worse than some of the awful shows which were done on the original series. I thought the way in which it was plotted and the way it was dealt with was an insult to the intelligence of the people who watched the show and the actors and characters in the show. None of the plot could have happened if all of the characters hadn't suddenly became morons that week."
The entire episode of "The High Ground" is the result of Dr. Crusher holding the Idiot Ball. In the opening, a terrorist bomb explodes nearby the cast and injures several citzens of the planet the crew is on, so Dr. Crusher recklessly goes over to administer medical attention without any security or other means of protection, as she is prone to do, and a couple minutes later one of the terrorists warps in, grabs Crusher and warps out, kidnapping her. The entire episode is spent trying to locate and rescue her. However, the viewer will probably notice the Idiot Ball moment when the viewer realizes that Crusher could have immediately pressed her combadge and said the 7 words she says practically every episode where Crusher is with a patient somewhere off of the Enterprise: "Enterprise, (insert number of patients plus Dr. Crusher here) to beam directly to sickbay" just about immediately after the bomb blast, avoiding being kidnapped and thus avoiding the entire plot of the episode.
Star Trek: Voyager: Captain Janeway practically is an Idiot Ball, and the members of her crew toss her around for exercise in each episode. In one episode, Janeway contracts a fatal illness that gets suppressed on a certain planet, and the crew is faced with a choice... leave her on a planet where she can comfortably live the rest of her life, or make a deal with the Vidiians, a race with a documented history of hijacking star ships and harvesting the organs of everyone inside. One unusually rational member of the crew makes it clear that negotiating with the Vidiians is a recipe for disaster, only to be ignored with the expected results. Winning decisions like this are made throughout the series, making you wonder if the HoloDoc is there to remind them to breathe every five seconds.
Why on earth would Sam and Dean even let Bela see the Colt, let alone leave her alone with it? They know she can easily unlock the safe and they certainly know that she can't be trusted.
They must have got it from their father. What was he thinking? Meg and her brother were obviously going to test the Colt out and they would obviously want to tear him and his sons apart when they found out that it was a fake.
And another one for Sam in Long Distance Caller. Leaving your unstable, few-seconds-away-from-losing-it brother alone in the hotel room, just telling him not to go anywhere and expecting him to actually stay? I thought you would have known better by now, Sammy.
For such a smart boy, Sam has grabbed a lot of idiotballs. The most glaring was in Nightshifter. He might be acting even colder/bitchier than normal and he certainly has all his attention on the job but telling Dean to get the guard outside where the news and police are waiting? Here's an idea, Sam, why don't you (y'know, considering you aren't the one being wanted for murder) do it while Dean takes care of the shifter. That would have made a lot more sense.
And then Dean in "Swap Meat". They live in a world full of demons and shape-shifters (granted, the tattoos block out the demons) and have angels hounding them to say yes to being possessed by Lucifer, in Sam's case, and yet Dean goes almost the entire episode without realizing that Sam is not Sam. Particularly glaring when Sam noticed Dean wasn't Dean in "Skin" immediately from a miniscule hint.
"The Song Remains The Same": Even after it is established that you can't change the past ("all roads lead to one destination"), Anna attempts to go back in time to kill Sam and Dean's parents. She also insists on walking in slow motion when fighting them.
The whole show has always been driven by idiot balls, from the beginning. The deals with the crossroads demon are the most irritating, but, also, a lot of their problems with the law would have resolved themselves if they'd just taken proper precautions and cleaned their crime scenes.
As of Season 6, the idiot balls now seem to be superglued to the Winchester brothers' hands. Most of their wangst—and the survival of so many individuals—could have been prevented if not for their incredibly dumb decisions.
In "Clip Show" Sam and Dean captured Abbadon. While they are interrogating her, Sam's phone rings. He steps out of the room to answer it... And for some unfathomable reason, Dean goes with him. They leave one of the most powerful demons they've ever encountered completely unattended. Predictably, by the time they return she has escaped.
Survivor: This has happened a lot, but one example is the Ometepe tribe in Redemption Island. Both teams were put with two of the biggest Creator's Pets in the show's history. Both of them are credited with knowing the game inside and out. The Zapatera knew that if any of them wanted to win, Russell had to go ASAP. (Unless your name was Stephanie Valencia.) Unfortunately, most of the Ometepe seemed to think that they could win against Rob and never once seemed to think about tossing him; the ones that did know were gone quick. Once again, Rob manages to be placed on the Buffoon tribe...and the stupidest tribe to ever play. Except that he didn't have a problem with their buffoonery.
Friends even had a Take That against the show in one episode, when they're all watching the show and Chandler says something to the effect of "Oh, this is the episode of Three's Company where there's some sort of misunderstanding." Phoebe replies "Then I've already seen this one," and switches the TV off. On the other hand, if it's constantly in play it's not the idiot ball: they may be just idiots in general.
Every main character in the first two series has been directly responsible for at least one of the crises they've had to face - Gwen in "Day One", Ianto in "Cyberwoman," Toshiko in "Greeks Bearing Gifts" and Owen in "End of Days". People also chalk Ianto's up to the fact that his love for Lisa has blinded him to the fact that, no, that isn't Lisa anymore (even though it looks like her)
If he knows that Captain John Hart is dangerous, why not go with him himself, instead of sending someone who he thinks that John may get the better of?
Using the resurrection glove to raise Owen just to give him two minutes to prepare for death (by which we mean "panic"), when he knows full well that good things do not happen when the gloves are used, and this is a new glove he just stole so whatever side-effects it might have are unknown. The side-effects? Summoning Death himself to walk the Earth and destroy all humanity. Nice job, "Captain".
1st season episode "Countrycide"
The team goes off to inspect a body all together as a group. In doing so, they abandon their camp with some of their supplies and equipment and leave the keys in their SUV. As far as they knew, there were aliens capable of who-knows-what on the loose, and were thus giving them access to their supplies. As would be expected, the SUV is stolen.
From the same episode, you have two people ready to kick down a door and probably get shot at, one's a rookie with little combat experience, the other's FRELLING IMMORTAL! Which one do you send in first?
How about the opening of "Fragments"? Lapse of judgment number one: "Hmm, there seem to be alien life forms registering... let's split up not once, but TWICE, despite the fact that we have no idea what this alien might be or if we'll even be able to fight it alone." And number two, which is somehow even WORSE?: "Oh, look, it's not aliens after all... it's bombs that are set to go off any second now. Let's all stand and stare at them instead of running away!" While the rest of the episode makes up for it, it's pretty hard to get through those opening scenes without outright laughing at the pathetic stupidity.
To summarize a conversation between Jack and Ianto in the radio play Asylum: "Let's mess around with this unknown possibly alien technology that appears to be extremely powerful! Oh, drat, we foolishly cut off all communication and gridlocked the traffic around us. Wanna hot wire a motorcycle and steal it? Hello pussycat! Meow!" (And that italicized bit is direct quote.)
Children of Earth miniseries
It has an Idiot Ball of a political kind, namely the British government, which, having made what turns out to be a massive blunder in 1965, tries to resolve its present consequences by attempting to cover its ass while at the same time giving the villains what they want, rather than spending any time looking into a way to stop them. Sadly, there may definitely be a bit of Truth in Television there.
Ianto's death is caused by one giant Idiot Ball shared by Jack and Ianto. Because their big plan to make the aliens go away is... to threaten them. Yup. That's it. Jack, who has been fighting aliens on Earth for over 100 years, and who was once a Time Agent and traveled with the Doctor, can't think of anything better than that. And Ianto goes along with it and with him... just because. So when the aliens call Jack's bluff and release a virus, there's nothing either one of them can do but die.
In "Walking Distance", Martin Sloan finds himself in his own past where he encounters his mom and dad and a younger version of himself. Instead of playing it cool, he acts like an idiot, scaring his mom and his dad. When he encounters the younger version of himself, he chases him, then later finds him and does the same thing again. Instead of offering some sage advice to his younger self, he gives himself a broken leg, which causes him to limp the rest of his life.
In "Escape Clause", Walter Bedeker is given immortality and is unable to feel pain. Instead of setting out to have a long and happy life, he falsely confesses to killing his wife and works in court to get himself convicted so he could try out the electric chair. He's given life in prison instead, although it's not explained what he would have done after going to the electric chair. It is at this point that he uses the "Escape Clause" which causes his own death rather than face life in prison. At this point, he has apparently forgotten that in addition to being ageless, he is also invulnerable. How easy would it then be to escape from prison if he doesn't have to fear injury or death? He could wait for an opportunity and make a break for the barbed wire or electrified fence and just climb over it. What are guard dogs or gunshots to someone who is invulnerable? In the very least, he could wait it out.
Three UFO's approach the Moon, but when Moonbase launches interceptors they turn tail and return the way they came. A conversation between Commander Straker and Colonel Foster reveals that this is the first time anything like this has ever happened. Shortly thereafter a meteorite falls on the Moon and communications between Moonbase and Earth suddenly fail for no apparent reason. Do you (a) consider the possibility that the meteorite is the cause of the communications malfunction as part of an alien ploy and check it out, or (b) assume that some scientists working nearby are the cause? Colonel Foster chooses (b) because he's annoyed about the scientists being there. It turns out that the meteorite (containing a radio jamming device) was dropped by the aliens as they retreated. Note that Commander Straker averts this, as near the end of the episode he uses Rewind, Replay, Repeat to achieve a Eureka Moment and figures out the truth.
The SHADO ship is preparing to land at Moonbase under computer control from the ground when the communications fail. Instead of switching to manual control immediately, the pilot repeatedly tries to call Moonbase to find out what's going on. His co-pilot sits by and does nothing, not even suggesting that the pilot switch to manual. The pilot finally decides to switch to manual control but it's too late: the ship crashes, killing both the pilot and the co-pilot.
V: In the original show, our hero Mike Donovan has been captured by the alien leader, Diana, and injected with a truth serum so that he will have no choice but to reveal the identity of the spy within her ranks. The serum doesn't work as well as it should and our hero is able to resist it. Does he pretend that it's worked so that he can lie convincingly to Diana and throw her off track? No. He defiantly lets her know that it hasn't worked by answering her first easy question (What colour are my eyes?) wrongly. Unsurprisingly, Diana's response is to inject him again. This time it works fully and he is forced to tell the truth, causing near disaster for the resistance.
When Stefan finally gets fed up with Damon, he drugs Caroline's drink with vervain, an herb that weakens vampires. Damon drinks from her and ends up poisoned and helpless. All Stefan has to do at this point is remove Damon's ring and leave him out in the sun (or stake him quickly, just to ensure no slip-ups). Instead, he leaves him in a cell in the basement, conscious, unrestrained, not chained to the wall, and the door isn't even padlocked (just bolted). Geez, Stefan, how the heck did you survive to the age of ~160 if you are THIS stupid?!
Pro tip for vampire hunters, especially if you have a magic compass that points to the vampire: hunt in the daylight.
Damon sometimes holds an idiot ball, such as trying ineffectively to poison a werewolf on the full moon, and then when she threatened vengeance just letting her walk away instead of, say, following her after she left the bar and ripping her heart out. Naturally she waited until the moon rose and came after him.
They should learn how to deal with their supernatural enemies. Kill It with Fire might work... You know, instead of letting them just "get better." The first time they kill something and it auto-resurrects, they may think "wow, that was freaky". The second time they can think "wow, what a coincidence. Talk about a black swan!" But the FIFTH FRIGGIN' TIME?? If burning doesn't work, at least TRY other things such as decapitation, instead of standing there trying to burn the thing over and over again.
Warehouse 13: Seems to be relying upon this for its plots more and more. You would think that agents who have been tracking down mystical artifacts for three years, seeing everything from earth-tremour causing walking sticks, to density manipulating spandex underwear, to a machine that can bronze people in such away that can be revived with no problems, that whenever shit doesn't make sense, they'd realize it's an artifact that caused and start trying to think of something that could do it, or looking on the computers. What does Pete do? Immediately thinks it's some wicked plot by the baddie du jour, rather than yet another artifact mishap which he seems to attract like moths to an open flame.
Several characters in The Flash (2014) do that, especially Barry. Being able to move faster than the eye can see should give him the ultimate advantage in any fight, and yet there are plenty of times his enemies are able to put up quite a fight, mainly to avoid making Barry seem like an invincible force. It's lampshaded several times, especially by Oliver, that Barry tends to rush into situations without thinking, despite the fact that he has plenty of time to analyze the situation and prevent the bad guys from getting the drop on him. That still doesn't excuse him being occasionally punched by the bad guys despite the fact that, to him, it should all be happening in slow motion, so he should be able to easily dodge any strike.
There's also Cisco, who designs a deadly weapon in case Barry turned out to be crazy or evil. Instead of putting it somewhere secure, he keeps it in a locker that gets robbed almost immediately. Not only that, but he doesn't tell his boss and his colleague about the weapon until after it's gone. And now one of the Flash's smartest and most ruthless enemies has a weapon he can use to freeze pretty much anything.
Appears repeatedly in Jessica Jones; there are many times where the mind-controlling villain Kilgrave gets incapacitated or captured, but escapes to cause more trouble only because someone gets a plot-convenient dose of stupidity. Lampshaded when Jessica's allies ask why she doesn't just kill him, and her reasons gets weaker as Kilgrave's body count rises.