* ''Manga/AngelDensetsu'' raises the Idiot Plot to an art form - the entire concept is that the main character unwittingly becomes the most fearsome gangster in Japan because of the whole cast's inability to communicate properly.
* Pretty much every time the Central 46 in ''Manga/{{Bleach}}'' make any kind of decision, horrible things will happen in Soul Society because of their sheer stupidity or {{Jerkass}} tendencies. Most of this occurs in {{Filler}} of course, but some of it is in the manga and thus canon, which means that all of the Council must be clutching an IdiotBall.
* {{Ecchi}} thrives on this trope since FeaturelessProtagonist is [[NecessaryWeasel essential to the genre]]. The protagonist and some/all members of the supporting cast are blind to any development or common-sense regarding basic human interaction and interpersonal relationships, in the name of extending the length of the show. The general formula is to [[ArcFatigue postpone the plot]] by fixating on random {{Filler}} and FanService.
** Related, but many ecchi and similar genres are often filled with characters who are abnormally clumsy, usually just as an excuse to have them landing in compromising positions.
* The ending of ''GundamSEEDDestiny'' hinged on the ''Minerva'' crew acting like complete idiots so that they would fight the [[TheAlliance Three Ship Alliance]]. The crew ignores [[BigBad Gilbert Durandal]] creating a fake Lacus Clyne and his [[OmniscientMoralityLicense plan to control people's destiny]]. They even let slide the fact that Durandal is willing to use his newly acquired doomsday cannon to ''blow away '''entire countries''''' if they don't agree to his Destiny Plan. Actually between all of the characters the idiocy extends to most of the series.
* In ''MobileSuitGundamAGE'', Nora could have been evacuated in advance if Flit just tell Commander Hendrick that UE is about to attack the Colony. Or if ANYONE in the Earth Federation put two and two together and figure out that UE is going to hit Nora next, something even a 14 years old kid can predict.
* Pretty much the entire second half of the ''Manga/CardcaptorSakura'' anime. It's painfully obvious to the main characters that Eriol is the cause of all the weird happenings, but no one is even the least bit suspicious of him. Most glaring is when Eriol buys a huge bag of sewing thread, cryptically says "There are many uses for thread" and wanders off. About five minutes later Shaoran is turned into a PeoplePuppet and forced to attack Sakura with, you guessed it, thread.
* {{Lampshaded}} in the ''WebVideo/YuGiOhTheAbridgedSeries'' spinoff ''Cr@psule Monsters'':
-->'''Alex "[[MostDefinitelyNotAVillain Definitely Not A Villain]]" Brisbane:''' Step on the map.\\
'''Yugi:''' Make me.\\
'''Alex Brisbane:''' Oh, come on. I'll be your friend.\\
'''Yugi:''' Look. There's no way I'm stepping on any freaking map.\\
'''Alex Brisbane:''' What if I told you there was ''candy'' inside the map?\\
'''Yugi:''' You've got to be kidding me. [[WhoWouldBeStupidEnough I'd have to be an idiot]] to fall for that.\\
'''Tea:''' Candy? That sounds pretty good.\\
'''[[TheDitz Tristan]]:''' Yes. Let's go get the candy!
* ''SonicX'' takes this to absurd proportions when ''everyone on the planet'' [[ArtisticLicenseAstronomy Fails Astronomy Forever]] for a couple of episodes, except Sonic himself, amusingly enough. Eggman rigs the moon to block out the sun, making it look like the moon pretty much stopped, along with the sun. Nobody finds this fishy because they've forgotten that the moon revolves around the Earth, and the Earth around the sun, not to mention the Earth spins on an embarrassingly wonky axis. Eggman takes the opportunity to try and {{brainwash|ed}} everyone with the lamps he sells, only to have his plan foiled by Sonic yet again, because he was the only one not holding on to the gigantic IdiotBall. The ball in this case being more of an Idiot Moon.
* In ''{{X1999}} TheMovie,'' the seven Dragons of Heaven each guard a magical barrier which serves to prevent TheEndOfTheWorldAsWeKnowIt. When the Dragon of Heaven protecting a given barrier dies, the barrier collapses catastrophically, and if all of the barriers are destroyed, humanity will be wiped out. So naturally, almost to a man, the Dragons of Heaven sacrifice themselves [[TakingYouWithMe to kill the Dragons of Earth]]... who are trying to destroy the barriers to wipe out humanity. (The manga and the TV series handle things much better.)
* In the anime of ''LightNovel/SakurasouNoPetNaKanojo'' -- the protagonist is specifically oblivious and thickheaded enough to be continuously embarrassed and ashamed of his female-lead just so hilarity may ensue. By a matter of fact, [[spoiler: In the end of the first episode, the protagonist came to a life-changing, self-aware conclusion that he is merely a cog within the machine, a simpleton that is too afraid to be important; and that conclusion -- [[{{Main/Snapback}} is completely forgotten in the next episode]]; making it possible to repeat the same mistakes throughout the show, looking for the exact answer he had already answered on the first episode through the many hijinks which ensues with it.]]
** Post exposition, it is explicitly shown that the protagonist has dealt with the tough, socially-inept, [[AmbiguousDisorder probably autistic]] heroine for almost a whole month; yet he is still shaken by her quirky, eccentric, abnormal behavior as if he just met her.
* In ''SoraWoKakeruShoujo'', Nami's sisters structurally fail to acknowledge her obvious depressed state, going so far as to kick her down even more, as Kazane does in one episode. Even after Nami's FaceHeelTurn, Akiha simply tells Nami to shut up instead of listening to her during their first critical confrontation. Yeah, that really worked, now did it.
* ''BestStudentCouncil'' in its entirety counts for this.
* ''Manga/DotHackLegendOfTheTwilight'' runs on this to an absolutely unbelievable degree to the point that its predecessor ''Anime/DotHackSign'' is genius by comparison. At least in Sign, the main character Tsukasa is trapped in the established game, and can't leave until he finishes despite how dangerous it is. In Legend however, the main characters learn in the first episode that the game they're in is glitched and dangerous, and unlike Tsukasa they have the ability to leave whenever they want to. So what do they naturally do? [[TemptingFate They continue to play the dangerous game]] simply because they can. This is exactly why the series was criticized so heavily at this point.
* [[Yuria100Shiki Yuria]] doesn't want to have sex with Shunsuke because if she does she'll become his life-long sex slave, being a SexBot and all. She's pretty sure she doesn't like that idea, even after she starts wondering if she's fallen in love with Shunsuke. That's all well and good, but Shunsuke also doesn't want to have sex with Yuria because he is ''bafflingly'' devoted to his [[DefrostingIceQueen chaste, ice-cold]] girlfriend who he rarely hears from and even more rarely gets to see. And anyway what kind of idiot makes a SexBot who is intelligent and emotional enough to decide they don't ''want'' to be a SexBot? [[ButtMonkey (oh right, that kind)]].
* ''MyBalls''.
** Simply put, the protagonist has a powerful demon sealed in his balls and can't ejaculate for a month or humanity will be destroyed. He does away with his PornStash, yes, and manages to deal with the various HornyDevils going after him, but doesn't stay away from his nymphomaniac-when-drunk coworker.
** Which gets even funnier because [[spoiler: he does leave her. AFTER the world is safe.]]
* One of the two major conflicts in the final arc of PhantomOfInferno relied entirely on one of the characters coming to a braindead misunderstanding and the protagonist not only [[PoorCommunicationKills not making any attempts to correct her]], but saying whatever he could to make himself look guilty and egg on the conflict.
* ''Manga/{{Suzuka}}'' would be about a dozen volumes shorter if Yamato didn't find a way to say or do ''exactly'' the wrong thing every single chapter.
* ''Manga/{{Naruto}}'':
** The short with the sports competition was an idiot plot. Naruto has a PottyEmergency, but his friends (somehow) fail to see this, and do things like keep prevent him from running to the men's room so they can take a picture, [[AssShove shove a baton up his butt]]. [[MurphysLaw And of course someone decided to close one bathroom for cleaning at *the* worst possible time]], so the other has a huuuuge line. [[PottyFailure This short, to the surprise of no one, does not end well.]]
** And on a much larger scale, the only reason there's any plot at all is because the BigBad apparently never considered personally capturing Naruto ''before'' he became powerful enough to challenge him. Given his teleportation powers, it would have been a simple matter for him to snatch Naruto whenever he wanted, but he doesn't actually try until after Naruto [[spoiler:gained full control of the Kyuubi's power,]] and is actually capable of putting up a fight. It wouldn't even have been hard, just pick any of the dozens of times before he got Jiraiya's supervision where he was either on his own, or only with other low level ninja and snatch him. It's not even in his own home village either, it's his JOB to routinely leave the village on little missions with only one mentor protecting him.
*** Here's your obligatory HandWave: It was because [[spoiler: [[FakeDefector Itachi Uchiha]] was in his way the whole time. Itachi joined Akatsuki to ensure it would not lay a finger on Sasuke or the Leaf. He would have intervened if Tobi tried to attack Kohona in ANY way, shape, or form. That includes going after Naruto. Up until Itachi died, Tobi put on an ObfuscatingStupidity act. When he kicked the bucket, Tobi made his move.]] However that doesn't explain why he didn't do it before then.
*** A possible explanation there verges on VoodooShark. Every other jinchuuriki was successfully captured without significant resistance by their village because none of them cared that their ''walking weapons of mass destruction'' were being stolen by an organization of criminals. The reason Naruto and B were left for last was simply because they were the only ones their respective Kages actually cared about.
*** The canon explanation is that the Kyuubi has to be sealed last, so it makes sense to leave it last- though, admittedly, that does run the risk of losing the Kyuubi if Naruto is fighting somewhere else and dies (the Kyuubi will eventually be reborn, but after an indeterminate time). It is also established that Tobi wanted Naruto and Sasuke to fight each other first (for reasons unknown, but possibly related to his obsessions- [[spoiler: since he is Obito, Naruto reminded him of his old self, so he wanted Sasuke to beat him to prove his old way of thinking wrong...as a wild guess]]). Its later established that he doesn't need the Bijuu ''per say'', just a certain amount of their chakra, though the full Bijuu is preferred. He manages to get both without capturing either B or Naruto, because sources of their Bijuu's chakra was elsewhere (in a lost limb of the 8-tails and with two deceased villains for the 9-tails, respectively).
** The Blood Prison movie, Naruto is sent to prison in order destroy the villain Artifact. However, Naruto was never told about any of this.
* "Stink Bomb", from the anime anthology movie ''Memories'' is about a salaryman at a pharmaceutical company who takes some experimental pills - thinking they're cold medicine - and becomes the vector for a chemical agent that kills everyone within several hundred meters from him. From then on, everyone just gets dumber. His immediate superiors call him out of a quarantine zone to deliver the pills to them. The JSDF try to kill him, but are so incompetent they just cause massive property damage and only exacerbate the problem. The American military screws things up even more by trying to capture him alive to get access to the chemicals. And throughout all this, the salaryman just '''can't figure out''' that he's the source of the obnoxious stink and no one EVER bothers to try explaining it to him. It's played for laughs, but galling all the same.
* In ''LostBrain'' the entire plot is basically one when FridgeLogic kicks in. The plot is based off [[VillainProtagonist Hiyama's]] plan of using hypnosis to remove human weakness with him controlling them having no chance at working, which any amount of additional research would have told him. The plot get even more stupid with the fact that [[ArchEnemy Kuonji]] and the police never seems to even try to investigate Hiyama even though all the trouble happening can pretty much be linked to him.
* ''Manga/LittleJumper'' would be a lot shorter if [[KidFromTheFuture Chimari]] had thought to look up her mother's name before going back in time. But then again, the IdiotBall ''is'' an Ichinose family heirloom.
* ''InfiniteRyvius'' would have been resolved if they had transmitted what happened to the rest of civilization, and definitely would have if they simply landed or had somebody leave the ship.
* In ''[[Anime/MobileSuitZetaGundam Zeta Gundam]]'' a lot of trouble would be avoided if the [[CoolShip Argama]] crew could control the catapult deck traffic better.
* ''GuiltyCrown'' episode 15 suffers from this. The entire plot for that episode depends on Souta and a few other unnamed characters acting like complete idiots, which eventually results in [[spoiler:[[TearJerker Hare's death]].]] [[FromBadToWorse From that point onwards it all goes downhill.]]
* The very first arc in ''VisualNovel/{{Clannad}}'' hinged on ''the entire cast'' failing to have the common sense to question or search out a reason for why one character was being unseen and forgotten by more and more of the school and town. One member decides to investigate alone, and [[spoiler:then immediately forgets and becomes unable to see said character.]] After that, they explicitly avoid this. [[spoiler:[[TearJerker It's not enough.]]]]
* Any pre-Unova ''Anime/{{Pokemon}}'' episode is guilty of this, as Team Rocket would show up in ''every episode'' wearing [[PaperThinDisguise easily transparent disguises]] and the protagonist would ''always fall for it'', then act surprised when Team Rocket tries to escape with their Pokemon. ''Post-Unova'' sees the light of day dawn on a loads more competent version of the Team Rocket Trio.
** A handful of later episodes have some dumb plots. [[TakeOurWordForIt Naming how many may take up too much space on this page.]]
* ''Guardian Force'', the latter half of ''Anime/ZoidsChaoticCentury'', features a truly spectacular idiot plot in which Hiltz, TheStarscream BigBad, wants to revive the [[SealedEvilInACan Ultimate Death Saurer]] to KillAllHumans until only his race, the Ancient Zoidians, remain. In order to do so, he needs [[MysteriousWaif Fiona]] to open the door to [[McGuffin Zoid Eve]]. The sensible thing to do would be to [[ManipulativeBastard trick]] her into doing so at the beginning of the series, when the Ultimate Death Saurer would be [[HopelessBossFight unstoppable]]. Instead, he goes on a totally pointless tangent, building the [[SuperRobot Death Stinger]] and using it to go on a [[ArcFatigue seven episode rampage]], giving the main characters plenty of time to build the superweapons and develop the skills and experience needed to defeat him. Hiltz didn't ''need'' the Death Stinger for his plan; in lieu of the revelations made during the final four episodes, everything which happened before comes across as ForTheEvulz in-universe, and [[MerchandiseDriven To Sell Toys]] out-of universe.
** There is however a very good reason why Hiltz didn't simply wake up the Death Saurer ASAP: The heroes have already killed a Death Saurer once before and they can do it again. The true purpose of the Death Stinger was to be a SacrificialLamb to power-up the Death Saurer. Given that the powered-up Death Saurer could no-sell a direct hit from the ''Gravity Cannon'', where even the Death Stinger died (temporarily) to it, it is reasonable to assume that the Blade Liger couldn't penetrate the Death Saurer's new armor to hit its core on its own power. The point about the Death Stinger's preceding rampage being For the Evulz still stands, though.
* The entire short "break-up" arc in the ''Anime/SailorMoon R'' anime could have been resolved by Mamoru ''telling Usagi the truth.'' Yes, he had prophetic dreams that she would die if they stayed a couple, but that did ''not'' require that he toss her to the curb and dump her. Then it gets resolved when Usagi finds out anyway and he completely caves. The real kicker? The dreams were being sent by the ''future'' King Endymion (Mamoru's future self) to try and strengthen the couple's love. That's right -- he broke them up to make them love each other more.
* ''Manga/BioMeatNectar'' is a rare dramatic example.
* ''Manga/BGataHKei'' is a story about a beautiful high-school girl [[HaremSeeker who wants to have sex with one hundred guys]]. If she could open her mouth and tell anyone that, the plot would have been over in ten seconds. [[JustifiedTrope But it wouldn't have been anywhere near as funny]], although its probably more due to ValuesDissonance if anything.
* In ''Manga/FullmetalAlchemist'', [[spoiler:Envy is eventually reduced to a powerless form]] and May Chang has to return to her home country. Trouble is, the plot requires them both to be in Central for the climactic battles. Arakawa's solution is to have the older and wiser people around May [[spoiler:put manipulative, sadistic Envy in a jar so that May can get the secret of immortality from him... the hideously nasty secret that ''they have all refused to use''. What's worse, she's supposed to take him to the Emperor of Xing, a man who she said five episodes ago should never know about philosopher's stones because he would happily perform the required slaughter! Envy talks her into going back to Central in about five minutes]].
* [[spoiler:The Black Knights betrayal of Zero]] in ''CodeGeass.'' Several years since the show has ended and it ''still'' is the most controversial element of the series. After [[spoiler:Schneizel reveals that Zero is Lelouch, former prince of Britannia, and a wielder of Geass,]] they take his word for it with almost no argument. They then hold [[spoiler:Zero/Lelouch]] '''at gun point''', demanding a confession from him. While [[spoiler:Schneizel]] was technically telling the truth, he was still their enemy, and no one bothered to question whether he was lying or manipulating them. They also don't figure out that their ability to mutiny proves that [[spoiler:Zero had not, as Schniezel claimed, Geassed them into obedience.]]
* Every single episode of the Island/Africa arc in ''NadiaTheSecretOfBlueWater''. There are so many holes in the "plots", that one could drive a truck through them.
* The entire plot of ''Anime/TenchiInTokyo'' hinges on the fact that, had this been done in [[Anime/TenchiMuyo another]] [[Anime/TenchiUniverse continuity]], it would not have worked.
* The Cell saga of ''Anime/DragonBallZ'' brought out the worst in most of the main cast. Every step in Cell's progress was the direct result of a protagonist's mistake:
** Piccolo's urge to destroy 17 [[HonorBeforeReason and save the day]] provided a huge energy beacon [[SpiderSense to pinpoint their location]].
** Tenshinhan using his [[CastFromLifeSpan Tri-Beam]] to incapacitate Cell would, given that it immobilised Cell for a long while, probably have been used to significant effect against Imperfect Cell - who he'd been observing before Cell absorbed Android 17 and transformed. It also took Android 18 far too long to even consider escaping while Tenshinhan was ''sacrificing his life for her''.
** Krillin's [[LoveMakesYouDumb refusal to destroy 18]] and Vegeta's [[BloodKnight urge to face a stronger opponent]] both allowed him to ascend to his perfect form.
** Cell wasn't immune, either - giving them ten days training could be reasonably considered a bad move on the off-chance they have some massive power-booster than takes a few days, such as, maybe, a YearInsideHourOutside training room.
** Goku dreaming up a ridiculous BatmanGambit in order to get Gohan - ''his ten-year-old son'' - to [[YouWouldntLikeMeWhenImAngry fly into a rage at Cell]] and tell literally nobody his plan until Gohan was on the battlefield being [[CurbStompBattle utterly crushed by Cell]]. [[spoiler:Subverted since it does end up working...eventually.]]
** Goku feeding Cell a [[EmergencyEnergyTank senzu bean]] and passing the fight to Gohan took out a prime opportunity to finish him off.
** And Gohan's [[SuperpoweredEvilSide blind rage and thirst for revenge]] caused Cell to become [[TakingYouWithMe truly desperate]], leading to Goku's HeroicSacrifice. However, even with all this, the saga is still widely considered to be the MagnumOpus of the series, and at least all characters' mistakes are in line with their established flaws and characterization.
* The entire ALO arc of ''SwordArtOnline'' probably could have been solved in minutes by Kirito just going to the police.
** The entire series period seems to only occur because not a single person in the titular game's development staff raised any objections about the whole "this game will kill people, which will in turn get us arrested and drive our company into bankruptcy all because the project leader wants to live out some power fantasy" thing. Not to mention that no government agency ''even tried'' to hack the game servers and attempt a rescue.
* In all continuities of ''Manga/{{Area 88}}'', many of the protagonists' problems could have been avoided if Shin had simply '''picked up the phone and called Ryoko''' to inform her of his deployment in Asran and Kanzaki's ambitions.
** Asran's civil war could have been avoided if Abdael had simply [[spoiler:shown King Zak the cryogenic chamber in which Soria was housed and explained why funding the country's medical system was vital to curing Soria's cancer.]]
* The encounter with Death 13 in Part 3 of ''Manga/JojosBizarreAdventure'' could've been resolved halfway through if everyone hadn't suddenly lost their [[GenreSavvy Genre Savviness]] and were unable to believe that a baby was a stand-user (when they'd already encountered a stand-wielding orangutan, [[ArbitrarySkepticism so they've certainly seen stranger things.]]) Even worse is when Kakyoin figures out what's really going on. Instead of trying to calmly and rationally convince the others (which isn't too much of a stretch because he's already one of the calmer members of the group,) he resorts to hysterics and only convinces them that he's lost his mind.
* The plan of the Capulet retainers in RomeoXJuliet is not ''that'' dumb at first glance, since it ''is'' a sound move to hide Juliet aka the SoleSurvivor of their Clan and [[RaisedAsTheOppositeGender make her live her early life as a boy]] to protect her from the Montague group. What's unforgivably stupid is to ''not explain to Juliet WHY she's forced into hiding and crossdressing until her DangerousSixteenthBirthday'': that means poor Juliet is completely unprepared to become the leaderess of the group and command them against the tyrannical Montague regime, and it takes a HEAVY mental/emotional toll on her. Not to mention, by that time she has already met the MadDictatorsHandsomeSon [[StarCrossedLovers and is falling for him...]]
* ''Main/JitsuWaWatashiWa'' is a deliberate example PlayedForLaughs. The entire series revolves around a bunch of idiots trying to keep incredibly obvious secrets from each other.