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.
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.
Of note: this very wiki has an individual Headscratchers page for nearly every character on the show.
Star Trek: Shuttlecraft have their own weapons, life support, shields, replicators, comm systems, sensors and power supply; logically they must also carry the key parts required for these systems to function such as dilithium crystals that could be cannibalized if needed. It is not an exaggeration to suggest that at least two thirds of all Star Trek danger plots revolve around one of these things breaking on the main ship/station, and also not an exaggeration to say that fixing said piece of technology would have resolved a good portion of these stories in about fifteen minutes. So how many times do the crew remember the existence of shuttlecraft in these situations? If you guessed almost none at all then you would be correct.
In the "Datalore" episode, 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 the 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 episode "Samaritan Snare" is accused of being an Idiot Plot by Trek writer Dennis Russell Bailey:
"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 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.
One of the most egregious examples is in the 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.
"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.
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.
There are many episodes where 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.
Star Trek: Enterprise: 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!
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 two 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 two 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.
Also the doctor who is roped into going along with Terri's charade via a ridiculous threat from Terri's sister that she clearly has no real ability to follow through on.
I Carly 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 to 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.
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. 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. You'd think explaining to Angel how his soul could be lost again would fit perfectly with their vengeance, since he'd then make sure to never be happy.
When the First Evil, Big Bad of season 7, starts appearing to people pretending to be their loved ones to break them...the gang keeps falling for it. No one thinks of using a secret handshake or anything to prove it's really them instead of the First Evil. Hell, a regular handshake would work because the visions are incorporeal. But everyone just keeps assuming it was really someone else nistead o the entity they know is out to mess with them.
Another Angel example was when they needed to bring back Angelus to get information from him. Early in the series (an episode called "Eternity") it had been shown that Angel could be temporarily turned into Angelus by being drugged and entering a fake state of happiness. Then once the drug wore off he'd be back to normal. No one seemed to come up with the idea of using this same technique again as opposed to permanently unleashing a psychotic vampire who then had to be cured.
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.
Whenever protagonists are taken prisoner on a Stargate show, the bad guys follow an incredibly stupid protocol: Put all the good guys in a single holding cell, so they're free to discuss escape plans. Don't make any attempt to monitor them to see if they're talking about escape plans (or anything else the bad guys might want to know). Make sure the prison door can be opened by some kind of device which is right in front of the door, and the device doesn't even require some kind of key. Store the good guy's weapons right next to their holding cell, and don't even bother putting them in a locked box or something. Naturally, all of this leads to Cardboard Prison stuff and the heroes always break out so they can go on with the rest of the plot. Granted, there are some exceptions to these rules, but there are many examples of stupidity, even by bad guys who should know better by now.
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 With The Cat". Phoebe thinks a cat is her reincarnated mother. Her friends humour her until they find out the cat belongs to a little girl who is really upset her pet is missing. Ross decides to stop humouring her because he doesn't want the little girl to be upset any more, so tries to make Phoebe give the pet back. All the rest of the gang continue humouring her because they keep wimping out of taking Ross's side even though they secretly agree with him. In the end, Ross is made out to be the bad guy for not being supportive of Phoebe, despite the fact he originally was until he found out an innocent child was being hurt in the process. In interviews, at least one writer admitted the plot line was pushed through because it was written by the show's producer Marta Kauffman who had just lost her own mother. The writer said that the plot would have been scrapped as soon as it was proposed but no-one wanted to go against Kauffman.
"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, Marta Kauffman, 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. Kauffman dismissed Cox's concern as impossible, concluding the actress simply did not remember doing it as a child; because she and her daughter did it, Kauffman completely believed that all girls everywhere do it. However, 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.
"The One With Sperm Donor". The writers made both Chandler and Monica have fertility problems (lazy sperm and a hostile uterus) because they didn't want one character to be "blamed". An episode or so later, this storyline kicks off where they decide to go the sperm donor route to solve the problem. This completely undoes the original intention of the writers by putting the problem squarely on Chandler's shoulders: a sperm donor won't change the fact that Monica has a hostile uterus, but her problems disappear and get ignored from then on in favour of a plot where the Friends become silly, and downright creepy, over their pursuit of a suitable sperm donor.
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!
The show by necessity required its villains to be idiots. The heroes were powerful and capable in close combat or when they had time to prepare a vanquishing potion. They were also frequently walking around in public, including Phoebe being something of a local celebrity whose place of work was well known. A demon with a sniper rifle or a bomb (including if they'd just thought to have left one inside the Halliwell residence one of the many times they teleported in) could easily have killed off the Charmed ones without giving them a chance to use their powers against them, but inevitably every fight seemed to involve the bad guy showing up, throwing fire balls that were easily ducked, then being killed.
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.
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.
The episode Dark Dynasty, however, takes the cake for being probably the biggest idiot plot in Supernatural history. The last part of the episode in which Charlie dies required so much incompetence that multiple actors and crew people have come forward to say that they argued that it made no sense and tried to offer up alternatives. In short, all the stupid things that had to happen for it to play out as it did:
Sam and Dean, who have encountered dangerous people and monsters thousands of times before and never fail to tie them up properly, chained a dangerous person up by only one arm, just so the writers had a way for him to pull himself out;
The guy had to somehow manage to travel a great distance to where Charlie was despite lacking an entire arm without bleeding to death;
Charlie had to leave a place where she was protected to travel to some random hotel while carrying an extremely important, dangerous artifact that people had already tried to kill her to get hold of. Why did she run? The show implies that she couldn't handle being around Rowena anymore, despite that Rowena hadn't really done anything other than be unsettling, and despite that Castiel had already taken Rowena into another room - and given that Castiel was a soldier for millenia, it's quite unconvincing that he couldn't figure out any other way to keep the peace;
Charlie had to make absolutely no attempt to escape once she was being attacked, despite that there was a window that was clearly large enough for her to climb through in the room (something Felicia Day apparently pointed out during shooting), nor call down Castiel when she realised she was in trouble considering that he now had his grace back and the two had finally met;
Charlie also had to somehow lose a fight with a man who had no arm and was bleeding to death, even though she'd managed to fend off a perfectly healthy attacker from the same family just a few episodes ago;
Charlie also had to have left said safe place with no more weapons on her than a single knife, despite the fact that she must have known she could be attacked again, and there's no way Sam would have let her around Rowena without protection.
And all of this is all the worse because Charlie is the most Genre Savvy character in the show - if anyone should know better than to go off on her own with no weapons or back-up, it's her.
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.
It is pointed out in the next episode that an investigation proved Brook was fake and that Sherlock was framed.
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 U.S. government gets the Idiot Ball with Pelant when he creates a fake Egyptian citizenship for himself and they let him go "home" without considering that the genius hacker might have doctored the records, and also forget that they don't let suspected murderers leave the country unless they have diplomatic immunity, which he doesn't.
It also never occurs to Hodgins to call the bank and say, "I did not authorize those transactions. Undo them immediately." The money isn't gone gone; it's just been sent to another bank electronically.
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.
"The Silurians" involves a sequence where the Doctor realises the Silurians have infected the potholers with a bacterial weapon, and informs Masters (an infectee) that he's very sick. Masters, despite the foul blisters on his arms, then announces he's going to London and no-one makes any efforts to stop him, not even the Doctor. Two episodes later, after Masters had got to London and spread the Silurian plague throughout the tube system, with chaos and people dropping dead in the streets, the Doctor even moons over the fact that if he'd just established a quarantine, everything would have been fine. The Silurians themselves spend most of the story convinced the humans are going to kill them despite the Doctor's best efforts to persuade them that they won't, and the humans spend most of the story convinced the Silurians are going to kill them despite the Doctor's best efforts to persuade them that they won't, and the Doctor spends most of the story convinced the two sides aren't going to kill each other even though they obviously are. The Brigadier purposefully defies the Doctor's orders and blows the Silurians up at the end out of sheer racism, and still the Doctor bothers showing up for work the next morning.
"The Android Invasion" has a plot twist based around the idea that Crayford, a character who wears an eyepatch, actually still has a perfectly functioning eye underneath it without his knowledge. This would require him to never take his eyepatch off for years - not to clean it, not to sleep, nothing. The Doctor comes up with several incorrect theories regarding the events in the village - first that they've landed in the aftermath of a radioactive incident, then that there's mass hypnosis going on - which is quite unusual for him; Sarah forgets to tell the Doctor that the TARDIS has gone missing; and Styggron's "plan" is without doubt the most incomprehensible and random Gambit Roulette any villain has ever attempted in Classic Who, which is saying something. The Doctor even speculates to an android Sarah about just one aspect of Styggron's plan (why's he bothering to create a simulated Earth village and fill it with android doubles if he could just wipe everyone out with a virus?) and the story never answers it. The DVD production subtitles spent a lot of time pointing out all of these plot holes and eventually conclude that Styggron is 'one of the most eccentric opponents the Doctor has ever faced... or else he's a twit'.
"The Brain of Morbius". The plot concerns Solon, a Mad Scientist who wants to transplant the brain of a Time Lord war criminal into a new body. Not having a complete body to use (save for his servant), he makes a patchwork body out of bits of various aliens that have been killed in spaceship crashes on the planet, but can't find a head big enough. Then, the Doctor, another Time Lord, shows up. Solon decides to use the Doctor's 'magnificent' head as the final piece of his makeshift monstrosity. So why didn't he just empty out the Doctor's brain and put Morbius in the Doctor's body? This Plot Hole was big enough that Terrance Dicks wanted his name taken off the script, and is helpfully pointed out by the DVD subtitles (which suggest that Solon is 'caught up in the blindness of someone struggling to assemble a flatpack piece of furniture'). It's also possible that Solon just really likes doing horrible things with bodies and a straight brain switch wouldn't be horrible enough.
In "The Girl in the Fireplace", the Doctor's solution to clockwork droids attacking Madame De Pompadour is to ride a horse through one of the time windows, breaking the connection to the ship in the future. He then engages in Talking the Monster to Death. However he is left trapped thousands of years from his companions and the TARDIS and it is only some flimsy writing that lets him get back. It doesn't occurred to him to find some other way to disrupt the time window (if smashing them can break them then it shouldn't be too difficult). This could be justified by him wanting to convince the droids to shut down but couldn't he have used the TARDIS to get there? Even if he doesn't want the droids to know about the TARDIS he could just materialise in another room a few minutes before the connection is broken. David Tennant actually pointed this out during recording and a line about not being able to use the TARDIS because they're part of events was hastily inserted, even though this is never a problem in any other story.
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.
"The Lodger" has the Doctor pretending to be a human, and clichés 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!" The writer has stated in his defence 'this is the Doctor acting like the Doctor, he's just doing it in a "normal" situation for once'.
"The Sontaran Experiment" involves the Doctor and his companions stumbling around a hillside and falling unexpectedly into into crevices whenever they're close to figuring out the plot or getting to safety. The titular Sontaran experiments are mostly nonsensical and border on torture For the Evulz - why is it necessary for a theoretical invasion to know what resistance the human ribcage has to crushing? Why would you test it by forcing someone to hold a weight above someone's chest until it fell down and crushed him? (This may, of course, have been intentional.)
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.
Deadwood: The first season and a half of this two-season series show that just about everyone in this World of Badass, no matter how big or small their hidden heart of gold, is willing to be just as ruthless and pragmatic as they need to be to protect their own, and that Al Swearengen is one of the most ruthless, most pragmatic, dog-shootingest of the bunch and also the only one capable of bringing all the movers and shakers of the town together for a common cause. Then Hearst shows up and everyone's Badass, proactive traits are buried in an egregious application of the Worf Effect. Their big plan for dealing with this existential threat to their way of life? To write a Strongly Worded Letter to the editor of the local newspaper and then send someone to a neighboring town to see about maybe hiring some guns, but then not do it in time to accomplish anything.
Let's be honest: You could play the "Stupid! You so stupid!" line from UHF for about half of the decisions characters on Once Upon a Time make. At least they're consistent in their style of bad decisions, like Regina constantly cutting her nose off to spite her face, all of Charming's plans having a critical flaw, Emma forgetting to actually use her lie-detecting, Grumpy's constant rabble-rousing, etc.
Lassie: The dog is smarter than all the humans put together during any given episode, adults included.
In "Marco Polo," a sixth-season episode of Modern Family, the Dunphys check into a single motel room while their house is being treated for mold. That's right—a single motel room. And they're packed in together. Clare secretly books a room of her own that she escapes to. Couldn't they have booked two hotel rooms together, with the parents in one room and the kids in the other? And why move to a motel in the first place? They could stay with Jay and Gloria or Mitch and Cam for free.
In The Walking Dead, the latter half of the fourth season is fueled by the stupidity of the Alexandria residents, who nearly get themselves all killed multiple times over due to easily-solved problems.
The town walls itself have Swiss Cheese Security, via an easily-exploited flaw in their design that allows normal people to climb over and out. Multiple people (Carl, Enid, Nicholas and Glenn) do this throughout several episodes, and several of them go out without weapons, thus putting themselves in danger.
The town residents are oddly flippant about their new arrivals, including Deanna (who should have been able to tell at a glance that they may be suffering from post-traumatic stress disorder). Deanna's flippant behavior towards Sasha at the party leads the latter to suffer from Sanity Slippage and leave the town for an extended period of time.
At a construction zone, the man leading the crew sees one of the sentries fall off a piece of equipment and injure her leg during a walker attack, and decides to leave her to be killed by walkers instead of rescuing her. Had Abraham not intervened, she would have died.
Aiden and Nicholas assume that Glenn, Tara and Noah are inexperienced neophytes who have never gone on a scouting mission, even though the latter trio are the ones who have to save him when the walker he inexplicably tied up to torture breaks free and nearly kills him. Even worse, Aiden's idiocy leads to his death when he tries shooting a walker wearing body armor and live grenades.
Deanna Monroe's son leaves the disillusioned and distraught Father Gabriel in charge of the town's main gate, which leads to it being left ajar and walkers entering the town. Had Rick not found out and dispatched the walkers, there would have been several fatalities or worse.
Deanna refuses to trust Rick when he tells her about Pete's abusive tendencies until it's too late, which leads to her husband having his throat slit by the enraged Pete at a town hall meeting.
Game of Thrones suffers from Idiot Plot most evidently in the Dornish arc of its fifth season. Jaime and Cersei's daughter, Myrcella, is currently in Dorne, and they've been sent a threatening message about her. So, Jaime - one of the most recognizable men in the Seven Kingdoms, by the way - decides to go and rescue her and bring her back home. With only one man, Bronn, to help him. Much idiocy ensues, including his trying to carry out the aforementioned rescue in broad daylight in front of Myrcella's fiancee. And after all that, Myrcella dies anyway because she allowed Ellaria Sand, who had already plotted her murder - of which Myrcella is well aware - to kiss her on the mouth, and naturally Ellaria was wearing poisoned lipstick.
One season 5 episode has Theo left home alone for the weekend, so his friends convince him to throw the obligatory "parents are out of town" party. Only it escalates to the point where there are far more uninvited guests than originally planned and the house gets utterly trashed. At no point did Theo put his foot down and send people home until it was far too late. And, given how much noise they made, it's a huge stretch to think that none of the neighbors called the police.
Vanessa and her friends use lies and deceit to sneak off to a concert in Baltimore. They don't even get halfway to their destination when their car is stolen in Delaware. Rather than call the police, they continue on to the concert where both their tickets and remaining money are stolen. To say Clair royally tears Vanessa a new one when she finally gets home is a massive understatement. It ends with Clair telling Vanessa that she will not believe anything Vanessa says at face value for a very long time.
Agents of S.H.I.E.L.D.: "Among Us Hide" attempts to set up ATCU Agent Banks as a Red Herring for Lash. The problem? Banks was accounted for during Lash's previous attacks. One of the characters investigating him, Hunter, was even in Banks' presence during Lash's first appearance. But the characters don't remember this, nor does the show seem to expect the viewer to, and the reveal that Banks isn't Lash is played completely straight.