Every episode of Freaks and Geeks. Every. Single. One.
In Falling Skies, despite the fact that the aliens are swarming over the Earth like locusts, marching everywhere in patrols and having ships scouring the skies - they are apparently unable to see large groups of humans wandering down streets in broad daylight, accompanied by noisy trucks, tanks and motorbikes, or to spot even larger groups camping in tents, again in broad daylight, right out in a huge open field, without making any attempt whatsoever to hide themselves. Also, after the alien invasion, women's abilities seem to have shrunk to the point where they are only able to cope with looking after the kids or dishing out dinner. 99% of the resistance fighters are male and the one woman seen so far who is a scout is clearly seen as an exception to the rule and an oddity.
The last part may not be as stupid as one initially thinks, given how pregnancy works if your race is facing possible extinction the cold reality is that more women than men are needed to ensure the species survives. Thus placing the women in combat would probably be a bad idea.
This show is a classic of stupidity. They capture an alien and then discover that it can speak through a once enslaved human. So do they try to interrogate it? No. They don't even ask one question.
Also Married... with Children, although the characters are all so deliberately cartoony it may actually play in the show's favor.
Lie to Me had an episode in which Cal Lightman had to determine whether or not a gang leader imprisoned for murder and awaiting a parole hearing was truly remorseful. Lightman and his team shared an Idiot Ball that caused Genre Blindness when the victim's wife testified at the hearing that she believed he was truly reformed, but they knew she was lying. They determined she wasn't being coerced, then scratched their heads until dramatically figuring out her motive at the last minute. Yes, a wizard did it. No, she wanted him free SO SHE COULD KILL HIM!
Lost Tapes. Characters often forget that videocameras have a VCR function that allows them to see what they just taped.
Primeval too. When half the plots wouldn't happen if the main characters didn't think they had to evade their security team, and everyone is convinced the Deadpan Snarker is a villain without any evidence...
Episode “Whisper,” in which Clark gets super-hearing and everybody's IQ drops 30 (desperately-needed) points. Even the villain!
Another glaring example is “Action,” where super-secretive Clark Kent stupidly rents his farm to a film crew for the Movie-Within-the-Show, "Warrior Angel". This is especially idiotic because only a few episodes previous, Clark's Super Powered Cousin, Kara, arrived and she's far less careful about keeping her secrets than Clark is, increasing the chances of being found out tenfold. Also, why a big-budget movie is being filmed on a goddamned Kansas farm rather than in California, or, better yet: Canada is never made clear.
Once the plots got a little longer and more complicated than finding out who the Monster of the Week is and having Clark throw them thirty feet, this has been happening all over the place. Mostly because Clark is so powerful he could stop everything bad from happening if only he would get off his ass.
Near the end of the season, Claire has several Damsel Scrappy moments, fleeing from people who obviously had her best interests at heart and into trouble on more than one occasion. Ando's deciding Hiro would give up if he had one more conversation with his dad, and thus going to take on Sylar(!) alone (!!), isn't much better.
In “Landslide,” Peter Petrelli telepathically eavesdrops on Sylar's plans to enlist the police's unwitting aid in attacking Ted Sprague… and then does nothing when he's subsequently arrested.
In “How To Stop An Exploding Man,” Mr. Bennet warns Parkman not to confront Sylar because “he'll kill you” – but one would think just telling him Sylar is telekinetic and has Ted Sprague's powers would be more viscerally persuasive.
The idiocy of the Company in controlling their superpowered prisoners seems pretty key. Depowering Sylar was a good idea, but leaving him alone and guarded by only one person, who he wanted to kill anyway with no means of knowing their condition, is roughly the worst idea imaginable. And Adam? Oh, let's just keep him in a cell. Next to the impressionable idiot with god-like powers. It's not like Adam has had decades to plan his escape or anything. There are so many more, it would probably be easier to list plot points that weren't pure stupidity.
Also from Season 1 regarding the big threat of the season, kind of. Peter knew that if he went to Kirby Plaza, he would wind up absorbing Ted Sprague's ability, and he'd seen that he was the one who caused the big boom in New York on that November night. Does he then decide to stay away and ensure that there is no way he'll gain the power to become a nuclear bomb? Oh no… he goes right to the one place he shouldn't and boom, gains the power which will blow up New York in a matter of days.
In season 3, a group of supposedly Bad Ass freakjob villains escape. Their big plan? Hurt people and rob a bank.
Also from season 3, basically anything to do with Mohinderance and his impromptu reenactment of The Fly.
Basically every time Peter shows up on screen and forgets that he can teleport or read minds (ie, always). Notable examples include not bothering to mind-read the villainous Adam to find out if he can be trusted.
Most of the things that have gone wrong in the series, have been either directly, or indirectly caused by Hiro. Actually, everything was indirectly caused by him, since he caused the formation of the company.
Also, Peter Petrelli meets his father, Arthur Petrelli, who was presumed deaddespitethe fact he hasn't seen him in years and is the head of a shady organization, does not stop to read his mind to understand what the hell was going on, and why he had disappeared for so long. Instead, he runs to give him a hug, and loses his powers (all of the ones he absorbed) to his father (who took in a lot of powers to begin with), launching the latter ever closer to A God Am I status, and the former being telekinetically thrown out a window by Sylar, as Arthur's way of saying "thank you" to his son. In fact, Sylar spared him death even if his idiocy didn't suggest so.
Arthur Petrelli is easily the stupidest villain ever. He absorbs every power Peter ever absorbed, which is a hell of a lot of powers, including teleportation, phasing, many, many ways to blast somebody to pieces, and healing, so they can't really hurt him back. In short, there's nothing to stop him from going over to Primatech and kicking everybody's ass. What's he do? He sits on his ass, drawing the future, and sends out his incompetent mooks to fail at doing his dirty work. Furthermore, he draws a future where Claire is dead, and he needs her alive. He could teleport straight to her, capture her, and teleport back to ensure her safety. What's he do instead? He sends out his two most psychopathic followers to capture her, and is surprised it didn't work. What an Idiot indeed.
As stupid a villain as Arthur Petrelli is, his wife, Angela, may well surpass him. Deciding that the best way to fight Arthur was to send Hiro to fetch Adam was just one of a long string of extremely questionable choices she has made over the course of the series.
The third season finale and end of Volume 4 takes the cake. Having finally rendered Sylar helpless, do they finally kill him? No. They need Nathan to convince the President to end the project, and Nathan's just been killed by Sylar. So they use Matt Parkman to brainwash Sylar into believing that he's Nathan, and using his shapeshifting to support this. And the episode ends with Sylar having been left in this imposture for weeks. Angela Petrelli, Noah Bennett, and Matt Parkman are just having Sylar walk around in Nathan's role and life permanently and expecting everything to be OK. Why? Why not at absolute minimum dispose of Sylar the instant he's finished with what you needed "Nathan" for? Better yet, since Peter had already absorbed/mimicked the shapeshifting power from Sylar, why not just have Peter pretend to be his brother for a little while, convince the President, and then pretend to go missing or die? And above all else, why not at least tell Peter, Claire, et al that "Nathan" isn't actually Nathan, so they don't trigger inevitable disaster via their ignorance next season?!?
The fourth season's finale (which also turned out to be the last episode of the series) certainly qualifies. After living through the events of volume 4, which were the result of the government learning about people with abilities, and hearing her dad plea on his deathbed that he wanted her to stay hidden and not reveal herself, Claire is compelled to jump off a Ferris wheel to do just that in front of national television. No reason is given for this decision, other than pissing off her dad who had poured his heart and soul out to her roughly ten minutes ago. Meanwhile, every other character in the series simply stands there gawking and dropping forced dialogue such as "she's going to change everything!", even though half of them had the power to stop her without making nearly as much of a scene (looking at you, Hiro!). After spending several episodes building up how much Claire-bear loves her crazy daddy, they have her just throw it all away for no apparent reason while the rest of the "Heroes" stand around and prepare for a repeat of volume four.
Too many episodes of Star Trek: Voyager to count, but it occurs in Star Trek: Enterprise, too. Either the main characters have to act like morons for the sake of "conflict" or "suspense", or the crew runs into some stubborn Aliens Of The Week who behave like belligerent jerks or fanatical idiots solely so that there will be a conflict of interests. SF Debris goes into much more detail regarding every idiot plot.
A prime example is the VOY episode "Innocence," where all of the conflict could have been averted had the alien dignitary explained to Janeway what was going on. Not to mention that Janeway readily accepts that the aliens age backwards and that the children Tuvok was protecting were actually their elderly.
A lot of the conflicts on Enterprise seem to stem from the entirety of Starfleet being so dumb that they don't even bother with establishing protocols for dealing with even a single, solitary thing the crew might have to deal with, up to and including first contact and planetary exploration, two tasks they were specifically sent out to do!
A few of the Next Generation plots had this too, like the 'Datalore' episode where Picard sends Wesley to check on Data, and when Wesley says that Lore is disguised as Data, no one believes him. Cue the obvious signs that Lore is disguised as Data.
In that episode, most of the cast had their idiot balls firmly in hand long before Lore actually set his plan into motion. Allowing a perfect double for your second officer to roam the ship freely is stupid. Allowing the second officer to go off somewhere alone with his perfect double is really stupid—especially when the perfect double is strong and fast enough to take on a small army by himself.
Thanks to the loss of records as a result of the destruction of Omicron Theta, Starfleet had no reason to expect Lore to be any different from Data. Until Lore's actions in that episode, they probably assumed he'd be basically the exact same person Data is, like 2 of the same product off an assembly line.
Was there an episode of TNG that involved Wesley Crusher and didn't invoke this trope?
One of the most egregious examples is in the Star Trek: Deep Space Nine episode "By Inferno's Light", in which the plot hinges on a captured Federation runabout being left unsecured and fully operational outside of a Dominion prison camp asteroid, close enough for transporter range, yet far enough away to make a getaway. Later lampshaded in the episode "Inquisition", in which it's used as evidence that Bashir is a Manchurian Agent.
Although possibly converted into Fridge Brilliance if the Dominion had intended to do more or less what was suggested in "Inquisition," and switch out one of the prisoners for a changeling or a programmed infiltrator, but didn't manage to make it happen before the escape went down.
In the Next Generation episode “Identity Crisis,” the crew know that LaForge has an affliction which will cause him to turn into an alien and flee the ship, so they leave him alone on the holodeck. Guess what happens next.
"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."
Although in a variation, it is justified for the antagonists of the week (it is fairly obvious that they are idiots), and several of the main characters act as intelligent as they usually are, raising valid concerns. Unfortunately, Riker (in charge for the episode) keeps overruling them for no adequately explained reason.
The TNG episode "The Perfect Mate" is one long idiot plot. Where to begin: Picard takes cargo onto the Enterprise without knowing exactly what it is. When told it is irreplaceable, he has zero people guarding the cargo bay or the object within. When Ferengi are rescued and placed on board the Enterprise, Worf doesn't place one person outside their quarters, nor do anything to prevent the Ferengi from harassing the Kriosian ambassador. Ferengi predictably try to steal the Kriosian cargo, causing the containment to fail. When it is discovered that the Kriosian ambassador is transporting a bride for an enemy planet, in order to seal a peace treaty, Picard is incensed, and insinuates that had he known that the cargo were a person, he would have never allowed this transfer. At this point, half the damn episode could have been avoided if Picard had done his homework on the people he was helping to broker a treaty for, and Worf had had even one person standing guard over either the cargo or the Ferengi. Bride gets out, and is basically a sex magnet for every male on the ship. Dr. Crusher is incensed that the bride is being confined to her quarters, although it is pretty much explicitly stated that if she goes near any male in her present condition, every male in the vicinity will literally proceed to jump her bones. At no point does Dr. Crusher offer to put the bride back into medical stasis, or even attempt to concoct something to suppress her pheromones to allow her to walk around freely, things we know Dr. Crusher is capable of. So Picard gives her leeway to move around the ship, with Data as her chaperon. Where does Data take this bride, who men would literally rip themselves to pieces for? A tour of some of the ship's more esoteric, out of the way facilities (such as the warp engines or utility systems), or the Holodeck? No: 10-fucking-Forward, the ship's bar. It never occurs to Data that it might be a bad idea to take a sex magnet who literally drives men mad with lust, to a locale full of men, filled with alcohol (fake or not), many of whom are there for the express purpose of hooking up. The guard now at the Ferengi door allows the Kriosian ambassador to meet unsupervised with the two Ferengi, allowing them to knock the ambassador out, thus adding an extra 20 minutes to the plot when Picard has to stand in for the ambassador at the negotiations and deal with the irresistible bride without the ambassador as a buffer between them. The entire episode only works because none of the crew do any of the things that it is their JOB to do, and have been seen doing in previous and later episodes.
Star Trek original series episode "Spock's Brain." It pretty much required Kirk, McCoy, Scotty, and the whole crew to act like they had the collective IQ of a parking meter.
"Profit and Lace" was an impressive failure because of this. For example, it turns out that a major player in the Ferengi economy is not only perfectly willing to discard his political beliefs out of a crush, but the subject of said crush was Quark in drag. Combine this with muddled direction in which every major player had a different idea about what the episode should be about or feel like, and the net result was a notorious trainwreck.
One episode had some people rob a bank of gold and then put themselves in suspended animation (which one of the robbers invented) for years in order to avoid getting in trouble for it. Had they just patented and sold the invention not only would they have probably made more money than they did in the bank robbery, it also would've prevented them from having to worry about the law in the first place. As the above-linked trope indicates, this is actually the problem with a LOT of villainous inventors.
One of the villains decides to increase his share of the take by killing one of the other robbers by deliberately destroying their only means of transportation.
Not only that, but when they decided to put themselves into suspended animation, they chose a cave for their hideout. None of them ever considered to put something over their chambers to block the potentially-falling rocks, which end up killing one of the men.
The dual pregnancies from the first season of Glee:
Quinn has to tell Finn that she got pregnant when he ejaculated in a hot-tub with her in it, which is completely crap, when the reality was she slept with Puck. Instead of lying about the hot-tub, she should have just had sex with Finn the moment she found out, and waited a week or 2 before revealing she was pregnant, and told Puck the baby wasn't his.
Terri has a hysterical pregnancy, and at first tries to get pregnant for real, but it fails, so she starts wearing a fabric baby bump. Instead of faking a miscarriage, she continues the ruse for fear of losing Will, her husband. Eventually she hits upon the idea of adopting Quinn's baby, when it's likely that everyone in the Glee club would be around the birth, and it'd be damn near impossible to hide the fact she now has Quinn's baby. There's also the question of exactly how far along the 2 women are. If Quinn was even a month behind, it'd mean the baby would be massively overdue. An even smarter solution would be to fake a miscarriage with her doctor, then offer to adopt Quinn's baby properly. Of course, it all comes crashing down, spectacularly.
iCarly has a few of these. In iGive Away A Car they believe a random kid who shows up on their doorstep, and claims to be the son of a local car dealership who wants to give them a car to give away as a prize on their webshow. They never thought to actually call or see the guy's father to check out the car that was supposedly on offer. In the end Nevel nearly gets their webshow shut down as a result of this.
LOST. Although there may be a number of instances, one that comes to mind is in the episode "The Variable". The protagonists are pretending to be (entry-level) members of the Dharma initiative. Daniel Faraday returns, and persuades Jack and Kate that he needs to visit the hostiles to speak with his mother. With some insane stretch of logic, they decide that it's dangerous and they'll need guns. So, they'll attempt to steal guns from the Dharma initiative so they can... what, use the guns to have a conversation with the hostiles? Wouldn't the guns just be more likely to make the hostiles shoot them on sight? As bad as an idea this is in theory, it pretty much turns out worse in practice. The Dharma Initiative catches them stealing the guns, and gunfire results. The three somehow manage to sneak up on the hostiles' camp, and with the largest stroke of luck, Daniel Faraday actually brute-forces his way into camp with his gun. However, the stupidity gets worse as he threatens Richard with the good old "I'm going to count to three" unless Richard tells him where his mother (Ellie) is. Seeing their leader was being threatened, Ellie comes up behind Daniel and fatally shoots him. It may have been a whole lot easier to simply go to the camp WITHOUT stealing the guns and just try to peacefully parley with them.
In one episode, JD is distraught about turning 30 without having accomplished anything on his "Things To Do Before I Turn 30" list. Understandable enough. Two days before his birthday, he finds out that a couple of the hospital's sad sacks are competing in a triathlon; very convenient, as "finish a triathlon" is one of the things to do on his list. You can guess what happens next. This would be a perfectly acceptable, if thoroughly silly, sitcom plot, if one of the other to-do list items wasn't "learn the difference between 'Senator' and 'Congressman.'" Five minutes with the Constitution or, even worse, 30 seconds on Google would have given him a solution and an end to his angst.
And when Dr Cox refused to go to Elliot's wedding with Keith. At first it seems a pretty Coxian thing to do, but things start to get stupid when Elliot refuses to give Dr Cox a piece of equipment - that could determine whether a patient lives or dies - unless he goes to her wedding. At least he had the courtesy to point out she was only marrying Keith for the sake of getting married, which started the train of events in which Elliot called off the wedding.
Season one ends with Veronica finding the tapes that implicate Aaron Echolls and then, rather than immediately going to one of the many state troopers who would certainly have been present in the house, since the governor was attending a party there, she drives away all by herself except for the full-grown man she somehow managed to avoid noticing hiding in the backseat of her Chrysler LeBaron. (The entire last third of that episode was more like a horror movie than a detective show, complete with a Made of IronBig Bad.)
In the third season finale, she singlehandedly went after a very powerful organization with absolutely no regard for the consequences. She doesn't even check for security while breaking into their mansion headquarters so of course she gets caught on tape. When another character states she just made some powerful enemies, she just handwaves it away with "It wouldn't be the first time." No, you idiot: This time you pissed off the kind of people who can make you disappear and the fact that this is America isn't going to save you. At the end of the episode, the head of the organization states quite clearly to a shocked Veronica (who literally thought she had won) that he's decided to make her life a living Hell because he knows she's responsible. He does.
In an episode of CSI: New York, an escaped convict's plan to flee to Canada involves hijacking a commercial airliner flying out of New York and landing at an abandoned airstrip in Montreal. Leaving aside the writers apparently not realizing that Canada does, in fact, have police who would respond to a hijacked plane entering Canadian airspace, there's also the stupidity of the plan given that the bad guy could have taken a bus or train to upstate New York, gotten off, and found someplace to quietly walk across the Longest Undefended Border in the World.
Not to mention the tiny logical hole of the fact that Canada is perfectly willing to extradite escaped US convicts.
Or the fact that only someone with a death wish would attempt to hijack a plane flying out of New York City after 9/11.
The BBC remake of Survivors has 99% of the global population killed by a plague. The survivors apparently suffered massive brain damage given their behavior. In episode #6 the protagonists head into Manchester, now a cesspit of disease populated by scavengers and countless unburied dead, to try and find a runaway teenager who doesn't want to be found. And they do this while being hunted by one of the local colonies who is trying to take them in by force under the pretense of being the new government. Naturally they make no attempt to protect their meager supplies from the desperate survivors who remained in the city. From the way they act you'd think nothing had changed and it was just another day out in the city.
In The Sarah Jane Adventures, "Mark of the Berserker", there's a serious issue. Rani gets the bright idea of leaving an Artifact of Doom alone, unguarded in the room, Sarah Jane shut down Mr. Smith while she was out, Clyde decides to spill all his secrets; Rani, when she starts to act, forgets to grab the Artifact of Doom. Clyde also, you know, spills his secret to his iffy father.
The miniseries Kingdom Hospital is about 80% filler. The hero is hit by a car, whereupon a monster appears and tells him that he won't die, if he helps them. An ambulance then takes him to the titular hospital, where he talks to ghosts and other presences. The reason he got taken there is because they want him to break their curse. Of course, they don't mention how, and he doesn't figure it out until the last few minutes of the finale. To top it off, the task at hand - drawing a fire extinguisher which becomes real in the dreamworld, and using it to put out the mill fire that killed the children which started the curse - takes all of two minutes.
The first two episodes of Season 4 are made of this. Buffy struggles to get along with her roommate, who initially seems to be just annoying but is later revealed to be a soul-sucking demon. Solution? Buffy moves in with Willow. But why on Earth weren't they already living together? Why is Buffy living in the dorms at all, when her house is so close to campus? Whose brilliant idea was it for the Slayer, who sneaks out every night to fight evil, to share a room with a stranger, who can't help but notice this suspicious habit, in an unsecured environment with all of her weapons so very easy to find? A bad roommate could have stolen them. A good roommate might have logically mistaken her for a criminal. There was no way this was ever going to end well, and the characters had an entire summer to see the obvious reasons why not and make other arrangements.
In a season 5 episode, the titular heroine goes on a vision quest in the desert. Meanwhile, Spike has ordered a robot replica of her to use as a sex toy. Buffy's friends stumble upon said robot and cannot figure out that the eternally cheerful vapid robot having sex with Spike is, well, a robot, and not their friend. All the wacky hilarity that ensues depends on Buffy's best friends not being able to figure out the difference between her and a robot, even though a few episodes earlier, it took them all of five minutes to detect that a woman they had never met before was the same kind of bot.
When Buffy is struggling to make money in Season 6, first trying to get a loan and later becoming an employee of the Doublemeat Palace, no one even once suggests that Willow and Tara could pitch in, despite them living in her house. It's probably because Willow and Tara, unlike Buffy, were in college, but there is such a thing as a college student with a part-time job.
Of course, the whole latter half of Season 2 is dependent on the gypsies who gave Angel his soul as a punishment deciding that if he becomes happy and stops being punished... he'll lose his soul and turn back into a psychotic killer with ambitions to destroy the world. Which not only guarantees he won't be being punished anymore, it's also kind of, um, dangerous.
But it's never said that the gypsies did this deliberately. It's simply the way a curse works; there always seems to be some kind of loophole, perhaps for reasons of Equivalent Exchange. When you've got spells lasting for eternity or that affect people over generations, the Universe or the Powers That Be would need a safety valve or the whole world would be full of cursed people.
The gypsies are clearly aware of the rules of the curse, so in that sense they did it deliberately. There's nothing to state that there's no way to restore a soul permanently and later events with Spike suggest that there is. Even if they can be excused by Deus ex Machina, the gypsies' handling of the situation is idiotic: They don't explain the rules to Angel but simply send Jenny to keep an eye on him, without bothering to tell her how the curse can be broken, and have her make a half-hearted attempt to keep Angel and Buffy apart.
The Series Finale was a major Idiot Plot. First, the control chair for the Ancient outpost gets destroyed because it was, at the International Oversight Advisory's insistence, moved from the outpost in Antarctica to Area51 in Nevada, despite the fact that the IOA was created specifically so that America wouldn't have sole control over advanced alien technology, and the non-American members have long been paranoid about exactly that happening, making it completely implausible that they'd demand the chair be moved from international territory to the middle of the United States. This is explained with the ridiculously flimsy premise that international treaty requires Antarctica to be demilitarized, ignoring the fact that a prehistoric structure could in no way be covered by the treaty. Later in the episode, when Atlantis tries to dial Earth and instead reaches a Stargate inside the Wraith ship attacking the planet, their response is to send a small team through to infiltrate the ship. Obviously, anybody who's not carrying the world's largest Idiot Ball would've just sent some Jumper drones through, and maybe followed up with a nuke just to be sure. That example also illustrates a recurring Idiot Ball in both Atlantis and the original. Dear Bad Guys, GUARD THE GATE!
The Goa'uld in Stargate SG-1 at least sometimes put some guards at the Gate at their major outposts, and sometimes they even bother to set up a BFG or two rather than just foot soldiers! The Wraith in Atlantis? Not so much. Not even for Gates inside their own spaceships. Oddly, the Goa'uld have on occasion made the same inexplicable error of having a completely unsupervised Gate on board one of their ships, despite the extreme security risk this presents.
Only Good Guys (humans, and Ancients) ever have an Iris. This may have been justifiable at the start as a “really clever idea” on the part of humans, but it's shown that the Ancients had one installed in their cities. And not a single civilization ever thought to copy this?
The entire retrovirus plot, especially in the Season 3 premiere, can be seen as one of Atlantis' crowning moments of idiocy. A pair of Wraith ships are on the way to Earth (the location of which the expedition themselves made accessible to them.) Their intercept strategy? Send the most advanced ship Earth has ever found into battle with no shields and make no real effort to defend it. At the end of that battle they have a strategically-priceless hive ship and a handful of Wraith prisoners. So they decide to give them all the retrovirus and stick them on a planet. It didn't end well the first time, so go ahead and do it again. Naturally the prisoners all rebel, they end up losing the hive ship due to their own stupidity and nobody seems to care. This foolish blunder also turns "Michael", the first test subject of the retrovirus, from a potential ally (due to his fellow Wraith rejecting him) to one of the Atlantis crew's deadliest enemies.
In the premiere, they can't seal a leak in the spaceship because somebody has to be inside the leaking compartment to push the button to close the door (proving that the Ancients were themselves carrying the Idiot Ball when they designed the ship). Meanwhile "Kinos", floating remote controlled cameras, feature prominently in the show. Nobody thinks to tape a pencil to the front, drive it into the compartment and push the button thus saving the day. This would prevent sacrificing a minor character to save the ship. Though the Senator was dying from internal injuries that they lacked the capacity to treat anyway.
A few episodes later, they combine dozens of Kinos to make a cargo-carrying hover sled, underscoring the earlier idiot plot.
Aden's utterly traumatized because his father Larry's drinking problem left him open to sexual abuse from his grandfather. After a collision leaves Larry concussed and kills another cast member, he's suddenly on the run from the police. At about this point, Aden and his (then) girlfriend Belle come across him in this state, and he persuades Aden to get him "one more drink for the road". So Aden drives off to the Bottle-Oh, and Belle, instead of staying to watch and make sure he doesn't do anything stupid, goes off with Aden. This provides Larry with the perfect opportunity to torch his own car and do a runner, leading, eventually, to a point where Aden just snaps and holds Larry, Belle and Rachel hostage while waiting for his father to die (it all works out fine in the end).
In fact, Aden and Belle held the Idiot Ball… pretty much the entire time they were together and most of the time they were apart and sometimes hand it to people in their immediate vicinity. The rest of that storyline consists of Larry not paying his mortgage because he's a wanted felon. Aden has been living somewhere else for months and would be no worse off if the house was repossessed but for some reason Belle decides to give him all her life savings so he can keep up the repayments, on the spurious ground that he could sell the house (which he couldn't, because he didn't own it). Then then go upstairs to have sex, leaving the money lying on the kitchen table. And because no-one locks their doors on the show, Larry steals it. Then it transpires the entire local police force have the Idiot Ball because Larry's secret hiding place is... his house. Where Aden finds him quite easily, leading to his attempt at patricide when his father turned out not to be as badly injured as he hoped. Then, when Rachel goes missing, the police question a suspect who they think kidnapped her. Said suspect knows that Rachel went to see Aden and has no reason to hide the fact but apparently it never came up in conversation... Oh-and the whole thing is resolved by a court case that says "It's okay to try and kill someone if you've been abused, just clean a couple of walls and we'll forget about it."
In the Mad About You episode "The Caper", several different couples go into the Buckmans' neighbor's apartment to fetch food. Each couple, when they return, comments on the neighbor's gorgeous painting. When the painting goes missing, each couple in turn is accused of having stolen it while they were fetching the food — despite the fact that the later couples reported it was still there when they saw it.
One episode of the Dawn French anthology series Murder Most Horrid sees her as a scientist who kills her nice but clueless husband after his bizarre and seemingly unmotivated behavior interferes with her attempts to invent time travel. Later, after serving a jail sentence, she returns home and completes her machine. She goes back to the day of the murder and, despite being apparently one of the smartest women on Earth, overlooks a number of fairly simple ways of preventing the tragedy; as a result, she ends up causing the bizarre behavior that results in the murder.
Indeed, she tries to get him out of the house by sending him on errands to collect various random objects. She somehow forgets that him turning up with those exact same useless things was a major cause of her annoyance with him.
"The One Where Ross Gets Married". Drama occurs when Emily calls off the wedding. Monica explains to Ross this is because at the age of five all women dream of the perfect wedding with the perfect guy and helps Ross fix it. The DVD commentary reveals the female producer came up with this based on her and her daughter's childhoods, but Courtney Cox had trouble with it because she never did any such a thing as a child. The producer dismissed Cox's concern as the actress simply not remembering doing it as a child, but many female fans over the years have reacted to the plot line exactly the same way Cox did.
"The One With The Sharks". Monica walks in on Chandler having A Date with Rosie Palms, causing him to jump and change the channel from porn to a documentary about sharks. Seeing which programme was on the television, Monica reaches the only logical conclusion: Chandler has a fetish for sharks.
"The One With Rachel's Phone Number." Joey gets tickets to go to a New York Knicks game with Chandler, who had already made plans to spend the evening with Monica. Not wanting to hurt Joey's feelings, Chandler instead lies and claims that he has to stay in Tulsa for business. This backfires when Joey hears Chandler in Monica's apartment that night and, believing that Chandler is away, suspects that she is having an affair with another man. This forces Monica and Chandler to go through an elaborate setup of lies to cover up the original one but things eventually fall through and Joey figures it out. Feeling guilty about trying to trick Joey, Monica allows Chandler to go with him to the Knicks game. Chandler and Joey begin heading to the game... and immediately turn back when Chandler points out that Joey had misread the tickets and the game is not until the next day.
Ross and Chandler's mock "memorial service" in "The One With The Memorial Service" definitely qualifies.
Like for instance in "Hyde School Reunion", Phoebe said a poem out loud causing an accidental spell. After several years, you would think that she would not say anything that rhymes out loud. And at the end, when the mortal held a gun at Phoebe's head, a mortal that knows about magic. What did Paige do? She killed him via demon rather than just simply orb the gun.
There are far more than a few in Charmed. In an early episode a reporter sees Prue using her powers and begins to stalk her to gain evidence of this. Not only do the sisters not try to find a convenient memory-erasing spell to get rid of the problem but when he sabotages Prue's car she agrees to tell the truth on camera. To make it worse, she never seems to consider calling the police to report him.
The biggest one of all for Charmed is an idea that could have solved at least a third of the problems the sisters had including Prue's death - use a spell that incorporates the inherent magical nature of the Halliwell manor to create a protective ward that will keep any evil beings, creatures or people from teleporting in or just walking through the damned front door. With every evil creature and his or her broodmate going through the manor like its Grand Central Station, you wonder why, over eight seasons, no one ever thought it would be a good idea to mystically lock the damned door!
Spooks series 9. The series arc revolved around Lucas North not being who he said he was but being an impostor. The whole problem could have been avoided had Mi5 done his vetting after meeting him face-to-face for his interview and not before.
In the episode "For My Lady", everyone thinks Charles is cheating on Caroline because he's doing some work for the attractive Widow Thurman. Every major character gets his or her turn with the idiot ball to make this plot work. Only Harriette acts like herself, but this helps the plot. Early in the episode, Widow Thurman gets some new China and offers her old China to Charles in exchange for some work he did for her. Mary is there and hears the conversation. Later, Charles gets the idea to do some additional work for the widow in exchange for the China. Here are the idiot balls:
Mary is the biggest offender. When she hears Pa is hanging out at Widow Thurman's after work, she should realize he worked something out with her for the dishes. Instead, she and Laura are convinced Pa is cheating on Ma.
Charles is not innocent, either. When he needs time off work to do the work for the widow, he tells his boss, Mr. Hansen that he needs to take some time off to take care of some things. Hansen is trustworthy. Charles could have said, "I'm going to do some work to earn a surprise gift for my wife." Instead, he's mysterious, which doesn't help when Carline starts asking about Charles. Charles also tells a series of white lies that make him sound like he's up to something.
Caroline gets suspicious when she asks Charles what he's been doing. Charles comes right out and tells her he's been working for the widow. Caroline asks what the job pays. Charles says he doesn't know yet. This conversation makes all the previous lies unnecessary. If he was just going to admit to Caroline that he was working for the widow, why act like he was at the mill the whole time? In the end, it all works out.
No-one ever realises the person causing trouble in every episode is just Robbie Rotten in a silly outfit. This is especially hilarious because his cover is blown at the end of EVERY episode, yet the townspeople will still fall for his Paper-Thin Disguise in the next episode.
A particularly hilarious example is when Robbie impersonates Sportacus. The other characters can't tell the difference despite Robbie being, among other things, 4-5 inches taller and a lot less muscular than Sportacus. The episode would be a very touching Aesop on friendship if it wasn't for the simple fact that Robbie and Sportacus look nothing alike, and they should have been able to tell them apart by looking at them.
Then there's the episode 'Double Trouble' where Robbie impersonates the mayor, and once again everyone falls for it, despite the fact that Robbie looks nothing like the mayor (for one thing, Robbie isn't a puppet).
The M*A*S*H episode, “Operation Noselift” has Private Baker convincing the doctors to arrange a nose job for him. Cosmetic surgery is against regulations. If Houlihan and Burns find out, everyone will be in trouble, so they have to concoct a plan to keep them from finding out. Instead of pretending Private Baker breaks his nose and needs surgery, they come up with a more complex and unnecessary plan. Private Baker is seen leaving the base on a two-day pass, then sneaks back to get the operation. Meanwhile, Father Mulcahy pretends to break Radar's nose with a baseball, all in front of Burns and Houlihan. Radar is rushed into the OR, the plastic surgeon arrives, Radar swaps out with Baker. The doctor performs the operation. Afterward, Burns sees Radar and questions him because his nose is fine. Burns realizes something is up and says he's going to get everyone in trouble, but just about everyone in camp is wearing a bandage on their noses, making it impossible to tell who had had the surgery. The problem with this is that it was completely unnecessary in the first place. They could have pretended Baker got hit with the baseball instead and that would be the end of the problem. This, however, wouldn't have given them so many opportunities to mess with Burns.
House is pretty rife with these, though 99% of the time it's the patient being the idiot. Many of the cases could be solved in two seconds if the patient didn't lie, deliberately hide parts of their past, or simply forget things that might be relevant. One that was on the doctors was when a patient died because one of them didn't ask all the proper questions regarding the patient's past, missing one that is a pretty damn big question. House doesn't do anything about it though because, really, how often is that gonna happen?
Half the time the patient is lying to keep a secret from someone in their life (who is always around when the doctors try to question them). This is one reason why real doctors speak to patients alone, so that the person can speak freely while assured that the doctor is bound by confidentiality.
Two episodes of Fear Itself exude this: Chance (see YMMV section in the article for an elaborate breakdown) and to a lesser extent In Sickness and In Health.
At least half the episodes in seaQuest DSV are this, but one in particular stands out. In the episode "Hide and Seek", a Eastern European dictator decides that for some reason or another, he needs to hijack the Sea Quest in order to get his son across a strait, for some obscure reason that the show never quite made clear. He does this by using Airwolf to take over the home of one of the Sea Quest's crew members, and then ransoms their freedom for passage. OK, even if we assume that the helicopter in the home invasion scene was not actually _the_ Airwolf, or something similar (and therefore could not be used to get these people where they needed to go, about 10-20 times quicker and more stealthily than the Sea Quest), there's one particular scene that makes the whole episode an exercise in stupidity. When the remainder of East Europe discovers that this dictator has booked passage aboard the Sea Quest, they assemble an armada to confront the ship, apparently with the intent of killing him and anyone protecting him. The armada uses a number of weapons to try and destroy the Sea Quest, to no avail. Finally, they resort to swinging a nuclear warhead on a CHAIN underwater: the explanation being that nuclear missiles were banned some time ago, however having mere warheads is more acceptable. The idea as presented in the story was that the nuke would be used as some kind of bang stick: hit the target and blow it up. It is clearly shown in the show that the only reason the Sea Quest does not blow up is because the warhead misses the ship by INCHES. Thus the idiocy: IT'S A NUKE!!!!!! If the goal is to blow up the ship, then why wait for contact? It's a NUKE!!! It's not like it's going to matter if it's detonated on contact, or only 2 inches away from the ship. I could buy the whole stupid part about everyone being so upset about this guy that they sent an armada that would certainly die if they used their weapon on him, but the idea of waving a nuke around like a stick, hoping to "poke" the target was so unnecessary it was stupid.
The Nanny: There was one episode where a trashy tabloid falsely alleges that Maxwell was cheating on his wife with Fran when his wife was still alive, even insinuating that he cheated with Fran on his and Mrs. Sheffield's honeymoon. Somehow, Max's eldest daughter Maggie—who at this point is entering college; Columbia in fact!—just instantly takes the tabloid's story as the absolute truth and refuses to give her father or Fran the benefit of the doubt.
An episode of Saved by the Bell has the boys catch Kelly's boyfriend Jeff cheating on her at a dance club. When they tell the girls, they come to the most obvious conclusion - Zack must tell Kelly. Right, the boy Kelly left for Jeff. Because of course she'll believe him. Of course this naturally sets up a big dramatic scene for Kelly to catch Jeff in the act.
Saved By The Bell has had many other examples of this, too. Such as the episode where they all get drunk at a party, get in a car crash and then get found out by telling contradicting stories to their parents about how their car got wrecked. Shouldn't Zack at least have thought this through a little more?
The episode In The Beginning involves Dean traveling back in time to try to kill Azazel. Conveniently he forgets several key facts in order to make the plot work. He forgets you can summon demons (his father previously summoned Azazel, and in the previous episode they summoned Castiel). He also forgets you can trap demons with devil's traps, salt, iron. All so that history can remain unchanged. All it took was his IQ dropping 30 points.
In one episode of the german Christmas show Beutolomäus the evil Piet Piestig wants to cancel Christmas, so he writes a letter to Santa asking that he cancels Christmas as his present. Santa actually considers this because he has to fulfill every child's wish, disregarding that considering Piets wish would mean he would have to disregard every single child on earth apart from him. Santa dismisses Beutolomäus´ advise that it would be a stupid idea with serious remarks that he can´t ignore a child's wish (even though he would have to ignore all wishes of other children and his ignorance is the reason the villain wants to cancel Christmas in the first place). The evil plan only failed because a friend of Beutolomäus saw that it was a grown man writing this letter with an expensive pen, which also disregards the idea that maybe parents write their children's letters.
Sherlock: Moriarty's plot to completely discredit Sherlock in The Reichenbach Fall is based on two things: Sherlock acting suspicious, and everyone in Scotland Yard conveniently forgetting about massive piles of evidence proving Sherlock couldn't have committed any of the crimes he's been framed for. Somewhat Justified in that Moriarty probably had about ten different plans for Sherlock's downfall (Richard Brook alone could've anchored an entire downfall plot), and the Idiot Plot was the one that happened to work best.
Richard Brook doesn't make any sense either. There are three possibilities for that identity:
He was real the whole time. Moriarty spent years being an actor just in case this kind of situation would happen to arise, which is problematic enough on its own. But if that's true, and Richard Brook is a pre-existing personality, why does no one recognize him and say "Hey, that's Richard Brook from that show!" during Moriarty's highly-publicized trial?
He was made up just for this plan. This plan could be defeated by ten seconds on YouTube, when someone does a search for "the storyteller" and finds absolutely fuck-all and subsequently realizes that something isn't right here.
He was made up just for this plan but Moriarty magically concocted a ridiculously elaborate set of fake shows, DVDs, etc. to fool people who looked into Richard Brook. Okay, fine. But then you run into the above, why does no one recognize him, and a subsequent problem, which is that no one will remember ever having seen Richard Brook's shows, and since he's an award-winning actor and all, that should seem kind of funny to the investigators.
To be fair to the show, in the next episode it is claimed an investigation proved Richard Brook didn't exist and Sherlock was innocent.
Sons of Anarchy became subject to this in season six, especially (but far from exclusively) in regards to Tara's plotline, which was made of this long before the finale, in which every character clung to the Idiot Ball long enough to get her alone in a room with a vengeful (and woefully under-informed) Gemma, who hollowed out her skull with a spaghetti fork, thereby causing Jax unspeakable amounts of agony. At least one critic was driven to invoke the Eight Deadly Words as a result. Other examples include the Sons' attempts to put gun-running behind them, thanks to the efforts of batshit crazy Irish Kings member Gaalen.
Pretty much the entire Pelant arc of Bones requires the team to be complete morons in order to work. For one thing, the team discover that Pelant can hack anything with a net connection, so what do they do? They leave the cameras, Angela's computer, and everything else the way it is. Then they leave their bank accounts untouched so Pelant can steal all their money instead of withdrawing everything they have and closing their accounts. This is just the tip of the iceberg as to the idiotic things the team has to do to keep this villain from being shot dead within 2 episodes. Worse, another unrelated plot arc involving Cam's identity theft could have been avoided entirely if the team had done this.
The Andy Griffith Show, like many sitcoms, had numerous episodes that would have been resolved in under a minute had someone decided to tell a slightly uncomfortable truth rather than try to spare someone's feelings. "Dinner at Eight" is probably the worst offender, when Andy was 'forced' to eat three spaghetti dinners in one night and be blamed for being late to one of them, when all he had to do was admit he didn't get a telephone message. Or call when he did get the message and say he was going to be late. Or if the host had called and made sure he had gotten the message. Or the host called when he didn't arrive and ask what had delayed him.
A season 7 episode of How I Met Your Mother has Marshall fretting about his employers seeing an embarrassing video of him on the internet (on an obvious Youtube Expy). So he goes to the guy who put the video up and begs him to take it down, having to jump through all sorts of hoops to get him to do so. This is ignoring the fact that pretty much all social media and video sharing websites have the option to report content as offensive. Marshall could have easily gotten the video taken down if he'd taken the time to actually notice the "Flag as Spam or Abuse" icon on the website.
Pretty Little Liars is a big offender on an episode-to-episode basis, but the basic premise is where it has its roots. Four teenage girls in thrall to their older, far more assertive and charismatic Alpha Bitch friend, are pressured into taking part in a nasty prank that goes wrong and results in a student being blinded and another student taking the fall for it. Following the murder of said Alpha Bitch, the four girls are harassed by a blackmailer who seems to know every detail of their personal lives. Rather than going to the police or their parents and exposing their initial culpability in a prank that would have resulted in nothing worse than disciplinary action or possible expulsion from their school, they do just as "A" tells them, the plot snowballing into an increasingly dangerous series of actions that actually could get them landed in jail or even murdered themselves. Even after multiple attempts on their lives and the deaths of several other characters, no one tells anyone anything.
In Doctor Who episode "The Lodger". Has the Doctor pretending to be a human, and cliches every "Alien trying to fit in" trope one can think of. Not to mention The Doctor, one of the most brilliant minds in the universe, has no idea what British Football is, and when the opposing team says "We're going to murder you!" The Doctor goes into rage mode
I am The Doctor! The Oncoming Storm! I refuse to allow any killing whatsoever!
He also very awkwardly interrupts Craig and his girlfriend completely oblivious to the fact that they want "Alone Time" despite Craig outright announcing it earlier. And after unintentionally making Craig jealous (All his friends and co-workers loving him more, which he really should have picked up on) he still seems surprised when Craig tells him "I hate you, get out!"
Though people have justified this by saying that The Doctor is particularly scatterbrained in this episode because he's swamped with the knowledge of the TARDIS exploding soon, Amy currently trapped in a time warp, weird disturbances emanating from the building itself, and Rory having just recently been erased from history. As well as the writer stated in his defense 'this is the Doctor acting like the Doctor, he's just doing it in a "normal" situation for once'
The 2014 The Lottery (not to be confused with the unrelated short story) starts with Dr. Alison Lennon successfully creating 100 fertilized embryos for the first time in ten years. She tells the government that she isn't entirely sure how it happened and more research needs to be done. The government fires her under suspicious circumstances, which starts her on a long path of distrusting the government and finding ways to subvert them. After a whole bunch of drama (and even water torture), the government decides to hire her back the very next episode and force her to...continue the very research she was planning on doing anyway. Seriously, all the subversive things that she does in every episode that follows wouldn't have happened had the government not decided to fire her and then forcibly rehire her a few days later.