History IdiotBall / AnimeAndManga

** Lelouch's IQ seems to randomly drop when someone he cares about is involved. The most obvious example is when [[spoiler: his close friend and potential girlfriend is killed]], which hinges on none of the important members of the Black Knights finding out but [[spoiler:they do.]] He then follows it up with including an insane male TykeBomb who wants to be Lelouch's brother... in the team tasked ''with saving Nunnally''. [[spoiler:Despite knowing that ''he'' killed his almost girlfriend.]] That's not a typo, he really did something ''that'' stupid.

** Light still takes the Idiot Ball to the face, however, [[spoiler: when he stakes his ''endgame killing stroke'' on a note that he kept in an ''unmonitored box''. It would have taken Light ''less than a minute'' to verify the death note would work, but instead confidently announces he's won, when ''just shutting up'' would have kept him in the clear.]]

** In ''[[Manga/JoJosBizarreAdventureVentoAureo Vento Aureo]]'', Narancia is under the control of a stand that makes him say things he doesn't want to say. Despite repeatedly saying things to the effect of "What did I just say?" and "I didn't mean that", [[spoiler: Giorno Giovanna]] is the only one to figure this out. The others only learn about this after the fact.

** When the task force sets out to look for Takada, Aizawa and Ide(who suspect him of being Kira) get into the front of their car, enabling Light to sit in the back and use the Death Note hidden in his watch without being noticed. Light lampshades this in his thoughts, exasperatedly noting that they're careless.

*** This is ''especially'' jarring if you happen to know about her role in ''LightNovel/AnotherNote''. It's like, "Did you learn ''nothing'' from your experience with [[spoiler: Beyond Birthday]]?!?!?!"

* An episode near the end of ''LightNovel/{{Slayers}} NEXT'' put the plot on hold just to show a fight sequence with a BrainwashedAndCrazy Gourry. Which wouldn't have been so bad if the villain hadn't slapped a really bad helmet on Gourry (and disguised him with nothing else) and also required the cast to A) Not see through the paper thin disguise B) Apparently forget that Gourry was kidnapped ''one episode ago'' C) Not assume that the blond guy dressed like Gourry and wielding the Sword of Light and fighting exactly like Gourry actually ''was'' Gourry. The characters would even constantly point out that he seemed familiar, but amazingly, despite the fact this is ''Slayers'', they seemed to lose their intelligent natures for the duration of the episode and the viewer was supposed to take it all seriously.

* ''Manga/JojosBizarreAdventure''
** A rather frustrating example occurs in the Death 13 mini-arc of Part 3, where ''everyone'' carries the IdiotBall. Everyone except Kakyoin refuses to believe that a baby with fangs (the villain of that particular mini-arc) could be a stand user while Kakyoin (normally one of the calmer members of the group) resorts to hysterics to try and convince everyone. The frustrating part comes from the fact that they're normally ProperlyParanoid, immediately assuming that anything unusual happening is the result of an enemy stand. They've already encountered a stand-using orangutan, not to mention Polnareff could use his stand since infancy, so a stand-using baby should be considered.
** From "Diamond is Unbreakable": "No, it's nothing. I just thought the rain sounded like Josuke's voice" - Jotaro, the oldest, smartest, most level headed and genre savvy member of the team, moments after hearing a distant bloodcurdling scream ''while tracking a serial killer''. There has been some debate about this scene, but this part is actually dumber in the anime, as it didn't adapt the rain very well. [[AlternateCharacterInterpretation And some fans just think Jotaro is half-deaf]] due to shooting himself in the head in the first chapter of ''Stardust Crusaders''.
** In "Vento Aureo", Narancia is under the control of a stand that makes him say things he doesn't want to say. Despite repeatedly saying things to the effect of "What did I just say?" and "I didn't mean that", [[spoiler: Giorno Giovanna]] is the only one to figure this out. The others only learn about this after the fact.

* In ''Manga/OnePiece'', during the Zou arc, Sanji is forced to betray the crew and return to his birth family, who want to marry him off to one of Big Mom's daughters. When Luffy and Nami track him down on Whole Cake Island, Sanji is forced to beat up Luffy in order to drive him away, resulting in Nami becoming furious with him and believing he betrayed them. This would be understandable, if not for the fact that it's the ''third time'' a Straw Hat had to seemingly betray the crew under duress, and tried to convince their crewmates not to come after them, as well as the fact that Nami was the first one to do so. One would think that she, one of the most intelligent members of the crew, would pick up on the fact that Sanji didn't go willingly. The idiot ball is even worst, when even ''Luffy'' realized that Sanji was forced to betray them.
** Subverted in Episode 831 during the Whole Cake arc. Multiple characters speak about the details of the assassination they are planning... in front of a sentient door that can hear see and speak. [[HeKnowsTooMuch The door is then cut to pieces.]]

** Urahara knows Orihime's powers will interest Aizen enough to kidnap her, but only tells Orihime to stay off the battlefield because she's unable to use Tsubaki. Rukia take Orihime to Soul Society to make Orihime a stronger fighter, but Orihime is kidnapped on her way back home. At no point does Urahara keep tabs on Orihime and, as an expert in breaking into the allegedly unbreakable Dangai, he'll know that location is as vulnerable to attack as any other. She would have been safer remaining at the Urahara Shop where any kidnappers would have to contend with him, Yoruichi, Tessai, Ururu, Jinta and Renji.

* A lot of problems in the second half of ''Anime/DokiDokiPrettyCure'' would have been solved had Mana not decided right then and there to ''not'' use her super special purification special attack on her friend who just got BrainwashedAndCrazy. She ends up with multiple chances to do so, but she (or the others) doesn't take it, instead trying IKnowYouAreInThereSomewhereFight speeches (or in Makoto's case, song).

** Subverted in Episode 831 during the Whole Cake arc. Multiple characters speak about the details of the assassination they are planing... in front of a sentient door that can hear see and speak. [[HeKnowsTooMuch The door is then cut to pieces.]]

* In ''Anime/MagicalGirlLyricalNanoha'', Lindy gripped the idiot ball pretty hard when she sent mooks to try to arrest ''Precia'', the most powerful mage in the entire series, who had already demonstrated that she was capable of magic powerful enough to disable a spaceship from another dimension. The results [[CurbStompBattle are predictable]].

* ''Manga/{{Naruto}}'': The ball gets passed pretty well.
** During the Chunnin exams in the Forest of Death, ''Sasuke'' gets hit by the Idiot Ball as he agrees to Orochimaru's offer of giving up the team's scroll in return for their lives, and Naruto calls him out on it.
** Later, during the invasion of Konoha, Orochimaru is in a position to kill the Third Hokage with a kunai. [[WhyDontYouJustShootHim Instead of doing that,]] [[ComplexityAddiction he backs off and summons reinforcements]] [[JustBetweenYouAndMe and makes a few long-winded speeches.]] The battle doesn't end well for him.
** IdiotBall moment of the story award goes to [[UnwittingInstigatorOfDoom Aoba]], who barges in to a room without knocking, and yells that [[AloofBigBrother a certain wanted man]] has entered into the village, which triggers the BerserkButton of a main character, and [[GreenEyedMonster things]] [[RevengeBeforeReason go]] [[MisplacedRetribution downhill]] [[ChronicBackstabbingDisorder from]] [[SlidingDownTheSlipperySlope there]].
** All the {{filler}} episodes of ''Naruto'' seem to involve a multitude of Idiot Balls as RuleOfFunny. In one episode (161), Naruto fails to recognize two people wearing obvious disguises to make them look like Guy and Lee, and misinterprets their increasingly deviant tasks as "taijutsu" training. In another (193), Lee fails to recognize his own sensei (who he idolizes) because of a weird wig.
** Sasuke dribbles the IdiotBall for a bit, his goals switching from "Kill people who were responsible for my childhood trauma" to "Kill everyone who lives in the same area as the people who caused my trauma", ''all because a man in a mask told him so, while said man also wasn't denying his own hand in causing said trauma''. To Sasuke's credit, he at least corners and confronts one of the supposed masterminds the masked man mentions to get clarification of the truth. It's all downhill from there once it turns out it really was all true.
*** The Uchiha Massacre was part of Itachi's plan to keep Sasuke loyal to the village. He wanted Sasuke to become stronger and to hate him, and him alone. To be thorough, Itachi {{Mind Rape}}s him, twice, leaving him comatose the second time, and mocks him for being weak both times.
** Konoha's handling of their two most prized, plot-relevant assets: Naruto and Sasuke. Naruto holds a powerful demon inside him, and Sasuke is the last ''loyal'' Uchiha, with the ability to copy techniques. Rather than train them in secret, they both attend public school. Naruto lives alone when he's introduced in the story and doesn't make any friends, and isn't put into any sort of mental therapy. Sasuke gets infected by a known terrorist, but rather than monitor him closely, they leave him mostly unattended, and he manages to walk out of the village with no one but ''one'' of his closest friends knowing about it. Naruto is allowed to leave the village perimeter with Jiraiya as his only bodyguard, despite the presence of a terrorist cell who want the Nine-Tails, and the village keeps zero tabs on Naruto (though granted, Jiraiya in spite of his eccentricities is the best possible choice for his safety).
* ''Anime/YashahimePrincessHalfDemon'' has one very idiotic decision made by Towa near the end of Season 1. [[spoiler:She has found out that Riku has been trying to reclaim the Rainbow Pearls from her, Setsuna, and Moroha, and that he is allied with Kirinmaru, the BigBad. For some reason, she completely trusts him and literally ''hands over her Rainbow Pearl'' to him without a catch. After he happily leaves, both Setsuna and Moroha point out that his boss is ''Kirinmaru'' and she promptly freaks out.]]
* Asa from ''VisualNovel/{{Shuffle}}!''. This requires some backstory. Her mother, Ama, is a homunculus, and had suffered greatly due to magic when she was younger. Although she now lives happily with her daughter, Asa inherits no small amount of magic as a result. Unused, this power will wreck havoc on her, and eventually lead to death. All she needs to do is occasionally use slight magic to stay healthy, but refuses to do so, since she doesn't want to remind her mother of her tragic past. Let me rephrase this. In order not to upset her mom, she decides to subject herself to a long, painful, completely preventable death in a hospital bed while her organs systematically shut down. While her mom, who ''knows she has magic anyway'', cries at her bedside. It takes her friend attempting suicide to force her to save her own life.
* Ranma from ''Manga/RanmaOneHalf'' (at least in the manga) is normally the TheAce combined with minor GuileHero. Able to lie and cheat and even try to find things to use against others. An example would be going to Nabiki's room to find things to manipulate her. Of course there were times when he fall and stumble due to his morals and therefore has the most ButtMonkey moments of everyone. In the Gambling King Arc, he suddenly becomes stupid. Unable to keep his face straight? Easily trick by the idiot Gambling King. It goes against everything shown in the previous stories. Thought people familiar with the anime will be at home in this Arc, due the anime Ranma being much closer to a savant or IdiotHero.
** All it would take is an umbrella and a travel kettle kept in a bag for Ranma to render his curse a trivial inconvenience at best. And as mentioned above, Ranma really should be far too cunning not to work this out by now.
** In one episode of the anime, Shampoo gets saddled with a cursed brooch that inverts her feelings for him, making her hate and want nothing to do with him. Rather than celebrating that one of the more troublesome elements of his daily life has resolved itself with no effort at all, he decides that his manly pride cannot accept this rejection and sets out to win her back.
* Irina Woods from ''Anime/MyOtome'' is one of Arika's smarter friends, but she gets handed this when she offers to allow Tomoe to return a book she borrowed from Professor Yohko when she could easily have done it herself. Tomoe uses this opportunity to sneak into the professor's laboratory to steal a vial of highly caustic acid, which she then uses to attack Arika.
* ''Anime/PokemonTheSeries'':
** The Whirl Cup. Ash is facing Misty's Psyduck with his Kingler. He already demonstrated knowledge of how to bypass Psyduck's headache powers in a previous episode, yet he still falls for it, giving Misty the win.
** In a later episode, James is feeling down because his Cacnea is having trouble learning a new move. Ash and co., for absolutely no fathomable reason, decide to help train it. That's right. They're willingly going to ''help'' Team Rocket, the group who have been stalking them, spying on them and attacking them since day one, get ''stronger''. When Dawn points out that Ash is being a monumental idiot, he brushes it off, saying it's their job to help Pokémon.
** Team Rocket actually grabs the ball ''constantly''. Among their exploits are running straight at a Frontier Brain while yelling at him to hand over the Articuno that was allowing him to use it in battle (without sending out any of their Pokémon).
** In ''Anime/PokemonTheFirstMovie'', Giovanni pretends he believes [[PhysicalGod Mewtwo]] could be equal to humans, while using it as his servant. He then decides to let Mewtwo know that he feels Mewtwo is only meant to serve humans. This is the Pokemon who, minutes after its "birth", slaughtered every last scientist in the facility it was cloned in and burned it to the ground. Giovanni is well aware of how powerful his "servant" is; he's the person who taught it to defeat wild and trainer-owned Pokemon with ease while wearing armor acting as a RestrainingBolt on its powers. He's seen Mewtwo at work. Furthermore, he knows that Mewtwo is an enhanced clone of [[OlympusMons Mew, the probable ancestor of all Pokémon]]. He is ''very'' lucky that Mewtwo only destroys Team Rocket's base while escaping from him in response. And AFTER all this, Giovanni STILL chases Mewtwo [[Anime/PokemonMewtwoReturns to the next region over]], bringing an army to try and stop him.
** Mewtwo erases everyone's memories of his existence, but for some reason it doesn't occur to him that he didn't do this to Giovanni, and it nearly costs him his life. Though to be fair, he might've thought Giovanni blew up with the entire Rocket base and presumed him dead, but he never bothered to check.
** Some people believed Ash had the ball glued to him most of the time during the BW saga, and it shows: from utterly forgetting how to catch a Pokémon without weakening it first, basing an entire strategy on using a single Pokémon in a Gym while theorizing he needed just one (Palpitoad in Elesa's Gym battle) to win it all...and completely forget about bringing other Pokémon besides Pikachu in the "unlikely" scenario (that happened) of his one "ace" mon getting taken down, to making his intelligence sub-par in general while the resident rival of the region would consider him a real nuisance.
** ''Journeys'' shows a strange example in Ash's third battle against Bea. In the first minutes of the match, perhaps to stretch the 2-episode fight, he basically forces Lucario to endure ''all three members'' of Bea's team dishing out move after move without it successfully hitting back once, though luckily it had quite a potent PlotArmor despite the species being known to be incredibly frail as a GlassCannon. The strange part comes because this is set after Ash's battle with Volkner, where he didn't hesitate to switch his Pokémon a lot even during the first minutes.
* Omi Tsukiyono from ''Anime/WeissKreuz'', who is supposed to be by far the ''smartest'' member of his team of [[HitmanWithAHeart Hitmen with Hearts]], gets hit by the Idiot Ball when he decides that the best thing to do with a [[BrownNote CD]] that causes [[DrivenToSuicide suicidal psychosis]] in half the people who listen to it is ''play it and see if it works''. It takes two of his teammates passing out for him to realize what a very, very stupid idea this was.

* An episode near the end of ''LightNovel/{{Slayers}} NEXT'' put the plot on hold just to show a fight sequence with a BrainwashedAndCrazy Gourry. Which wouldn't have been so bad if the villain hadn't slapped a really bad helmet on Gourry (and disguised him with nothing else) and also required the cast to A) Not see through the paper thin disguise B) Apparently forget that Gourry was kidnapped ''one episode ago'' C) Not assume that the blond guy dressed like Gourry and wielding the Sword of Light and fighting exactly like Gourry actually ''was'' Gourry. The characters would even constantly point out that he seemed familiar, but amazingly, despite the fact this is ''Slayers'', they seemed to lose their intelligent natures for the duration of the episode and the viewer was supposed to take it all seriously.
** Many people in the Slayers universe in general tend to juggle the idiot ball quite profusely around the protagonist. In a land where Lina Inverse is not only known as a skilled sorceress but actually [[TheDreaded feared]] by bandits because she's known to hunt them down, incinerate them with magical fire, and then steal their loot, she seems to run into no shortage of loud-mouthed buffoons willing to [[TooDumbToLive comment on her]] [[BerserkButton small breasts, make fun of her height,]] or refer to her by one of several unflattering nicknames.
* Interestingly, in one volume of the ''Manga/BoboboboBobobo'' manga Poppa Rocks/Don Patch uses an actual "Idiot Ball" as a weapon. Whoever is hit by it would "get an 'A' on his exam... by CHEATING!"
** Don Patch also has an attack where he injects you with a serum that makes you think like he does. Beauty didn't take it well.

* In ''Manga/RappiRangai'' the hero has a tiny horn that caused him to be beaten and ostracized by his village as a child. This FreudianExcuse causes him to flee like mad whenever he thinks torches and pitchforks might be around the corner. Even when nothing is actually wrong. Even if it'll completely undo his [[UnwantedHarem Ninja Harem's]] plans. Even [[spoiler: on his wedding day when his would-be bride ''says to his face'' she thinks the horn is cute. Even when the Ninja Harem ''tells him that his bride thought it was cute''.]] In his defense, they were pretty severe beatings.
* ''Manga/SchoolRumble'' is more like a case of "pass the Idiot Ball". There's usually an [[ButtMonkey idiot of the week]].
* ''Manga/TsubasaReservoirChronicle'', episode 48. After collecting 13 feathers on screen and who knows how many off screen, all with pink markings, [[spoiler: King Chaos]] just hands them a number of purple, blue, and orange feathers. And not one person stops to question that. [[spoiler: It's a trap.]]
* ''VisualNovel/HigurashiWhenTheyCry'''s Keichii carries one of these towards the end of Watanagashi-hen, when he agrees to go for a walk in a secluded underground dungeon with a self-confessed murderer who freely admits to having mental issues that make it difficult to control her behavior even when she doesn't actually ''want'' to hurt anyone. She's able to hold herself together enough to let him go after only torturing him a ''little,'' but before she does she warns him never to get near her again. Guess what happens when he decides to ignore that warning.
** Although, to be fair, she did confess that [[spoiler: her sister was still alive and being held on the dungeon.]] Still, he could've gone with Rena or simply without [[spoiler: Shion]]. Or he could've waited for the police to arrive first, that works too.
** In the game version and the manga, he had a better and more justified reason for ignoring her warning -- namely, [[spoiler: he was giving Mion the doll that, by not giving it to her, started the whole thing]]. Still pretty dumb, though.
* It seems like Momo's class in ''Manga/PeachGirl'' is forced to carry this, as it regards Sae. Her schemes have hurt or enraged almost everyone long before the first time she is caught out on her campaign against Momo. Yet the class is ready to lynch Momo, and on more than one occasion, based on setups they all know Sae's capable of, and they all say very clearly that they know this when she is exposed. Worse, even when exposed, Sae getting anything stronger than the cold shoulder seems out of the question, since no one wants to do to her deservedly what they did to Momo based on whipped up frenzy. Momo's first boy friend actually believed Sae that it was okay to kiss her as a way to practice for Momo.
* In ''Manga/{{Bleach}}'':
** Urahara knows Orihime's powers will interest Aizen enough to kidnap her, but only tells Orihime to stay off the battlefield because she's unable to use Tsubaki. Rukia take Orihime to Soul Society to make Orihime a stronger fighter, but Orihime is kidnapped on her way back home. At no point does Urahara keep tabs on Orihime and, as an expert in breaking into the allegedly unbreakable Dangai, he'll know that location is as vulnerable to attack as any other. She would have been safer remaining at the Urahara Shop where any kidnappers would have to contend with him, Yoruichi, Tessai, Ururu, Jinta and Renji.
** Zommari could have ended his fight with Byakuya immediately by going for a headshot before Byakuya knew what his power could do. Instead, Zommari used his own arrogance to try and bring down Byakuya's arrogance. Lampshaded during the battle when Byakuya bluntly tells him how much of an idiot he's been to reveal his powers too quickly and freely.
** Tousen wasted time lecturing Zaraki during their fight, despite Zaraki being incapable of hearing him. It gives Zaraki time to adapt to Tousen's Bankai and defeat him. When Tousen later fights Hisagi and Komamura, he decides to use Resurrección without testing it before hand. He had been toying with his opponents previously, but after the power up becomes so intoxicated by his newly-gained sight that he drops his guard and gets ambushed by Hisagi. Hisagi lampshades this at the end of the battle.
** The Vandenreich are initially introduced as ruthless opponents who take advantage of the Shinigami habit of explaining their powers. As they become more exposed to the Shinigami, they become more talkative and also start explaining their powers. The Vandenreich leader and his second-in-command discuss this being a problem, but two get KilledMidSentence and the one who steals Chojiro's Bankai thinks his success makes him a match for Yamamoto. He's wrong. As Nodt is introduced as particularly calculating and ruthless to defeat Byakuya, but is later seen joining two other Sternritter in ambushing Yamamoto. It forces Yamamoto to look away from his opponent to deal with them, but that's [[OffhandBackhand all it does]].
** Cang Du is mostly a silent character until he confronts Hitsugaya. He explains his personal beliefs, which buys enough time for Hitsugaya to benefit from Urahara's intervention to restore his Bankai. Bazz-B almost killed Hitsugaya, but Cang Du wastes it. Lampshaded in-universe by both Bazz-B and Yhwach himself.
** Kyoraku's decision to make Zaraki more useful in battle against the Sternritter results in getting a Shinigami killed, something he knew in advance would happen and carried through anyway. [[spoiler:His first act as Captain-Commander is to order Unohana to [[DuelToTheDeath power up]] Zaraki. The Gotei 13 loses just over 2500 out of 6000 men in the first Vandenreich invasion and the Royal Guard prioritises the Soul King over helping out. Even though Yamamoto never let her fight, and Zaraki does get powered up (but not enough, it turns out), it costs Unohana her life and the Gotei 13 its best healer.]]
* The ''entire'' storyline of ''Manga/AngelDensetsu'' juggles with so many idiot balls that you have more or less every example, subset or relation of this trope. In spades. We even have WordOfGod that Kuroda is the designated carrier and master of the Idiot Ball, for the express purpose of plot advancement. Behold the [[SwordOfPlotAdvancement Idiot Ball of Plot Advancement]]! The worst thing? It's so well done it's almost believable.
** The SelectiveObliviousness of the main lead does not help a bit.
** There's so many balls zipping around it even takes a while to understand ''who'' the ButtMonkey is. (It's [[spoiler:Ogisu]])
* Greed of ''Manga/FullmetalAlchemist'' has the power to make himself invulnerable in a way that can only be circumvented by five people in the world. He rarely extends the power beyond his arms; he doesn't like covering his whole body, because [[OneWingedAngel he thinks it makes him look ugly]].
** He also can't regenerate and use armor at the same time, as Ed notices during his fight after using a transmutation technique that makes Greed's carbon armor useless. [[spoiler:King Bradley/Wrath]] doesn't give him time to do either during their first fight.
** In ''Anime/FullmetalAlchemist2003'', Greed goes full-armor when it's serious business. Any other time, he's still armored below the skin, as Izumi can attest to. "So, how many fingers did you break when you hit me just now?"
* In ''Manga/HajimeNoIppo'', Kobashi, a physically weak boxer, uses a boxing style that goes for a win via points and exhausting his opponent instead of going for a knockout. However, during the last round of his match against Ippo, Kobashi, having a two point lead and an opponent too exhausted to catch him (meaning that all he has to do to win is dance around until time runs out), suddenly decides to try to go for a knockout against an opponent known for [=KOing=] all of his opponents. This idea ends about how you'd expect it to. This is made even worse by the fact that Kobashi had apparently put a great deal of research into Ippo's fighting style before the match. Kobashi even lampshades it after he wakes up.
**It actually makes more sense in context. Kenta fights the way he does because he doesn't have the muscle to win by KO, and instead plays to his advantages. During the end of his fight with Ippo, when he has Ippo at his mercy, he lands a really good hit on him and is blown away by how good it feels and pushes to get a KO.
* ''Manga/YuGiOh'':
** Jonouchi duels Kaiba for the first time in Duelist Kingdom. After Kaiba plays his Rabid Horseman on around the second or third turn, Jonouchi throws out several weak monsters in attack mode, despite the fact that there's a defense mode that is used in almost every duel before and after this. It's unknown why Jonouchi wouldn't use it, besides perhaps not knowing how the new duel disk worked. However if this is the case, he could simply have just asked Kaiba how the machine worked (this was the first duel between two living humans to ever use the technology), but given his animosity towards Kaiba, he’d rather lose than ask him for help.
*** After Kaiba played Horseman the first monster Jonouchi sent after it was Swamp Battleguard, a monster with 1800 attack points. After it was destroyed, Jonouchi sent Axe Raider with 1700 points to avenge Battleguard. Yeah, he tried to send a monster that was weaker that the first one thinking it would do better. And all of the other monsters Jonouchi attack R.H. with also have 1800 attack points. Jonouchi, if the first 1800 attacker couldn't beat Kaiba's monster, what makes you think the others will? It's no wonder Kaiba insulted him to no tomorrow over it.
** In the beginning of the anime's second season, Yugi, who was on the way to school with Anzu, was naive enough to lend the fortune teller his Millennium Puzzle in order to get his fortune told, and he would have ended up [[spoiler:dying in a warehouse fire]] if it weren't for Jonouchi and Honda, although at the time he was desperate for any clue he could find about the Pharaoh.[[note]]This only applies to the anime. In the manga Yugi nearly dying in a fire over the Millenium Puzzle was part of the Dungeon Dice Monsters mini-arc, and it was taken from him instead of handed over.[[/note]]
** Arguably, his [[spoiler:attempt at a HeroicSacrifice]] later in the same season during his forced duel against Jonouchi as a part of Marik's plan could be seen as this. [[spoiler:Yugi has just absorbed Meteor of Destruction with Mystical Ref Panel, and decides to nearly kill himself with it so Jonouchi could be free, but Jonouchi tearfully calls him out on this and gets Red-Eyes Black Dragon to attack him so that he could free Yugi.]]
** Yami Marik's victories over Mai and Yami Bakura were achieved thanks to their fatal misplays. Mai had the opportunity to defeat him with her Harpie Lady Sisters, but she decided to tribute them to summon Ra... which she couldn't control and it remained in its Sphere Mode until Yami Marik unleashed it and defeated her. [[note]]Her doing this was more justified in the manga, where Marik had the advantage throughout the entire Duel, and where Marik's Viser Des would have shrugged off the attacks completely due to its battle-immunity, which would make this more of an AdaptationInducedPlotHole.[[/note]] While Yami Bakura could control Ra, Ra had 0 ATK, but 3450 DEF and is very hard to defeat since it is also immune to most effects. Despite this, Yami Bakura tributed his StoneWall for his Dark Ruler Ha Des, forgetting that he "traded" his Spell Card ''Monster Reborn'' during the duel, which gave Yami Marik the opportunity to get Ra back. Then again, Yami Bakura assumed that it wouldn't be a problem, since Ra's default attack power is dependent on the attack power of the monsters tributed to summon it, meaning that its attack power would be 0 if it were special summoned. [[spoiler:Too bad only Yami Marik knew of Ra's secret ability that allows the player to convert their Life Points into Ra's Attack Points.]] On one hand, to be fair to the two of them, Ra's highly mysterious nature means neither of them actually knew how the card worked until it was too late, but even then it ''still'' counts, since trying to use a card you know nothing about when you have a much simpler method of victory in hand seems like a totally unnecessary gamble, especially for Yami Bakura, who should've realized there was more to Ra than met the eye.
* On the same series, we have the infamous ending in ''Anime/YuGiOh5Ds'' of the [=WRGP=] duel between Team 5Ds and Team Unicorn. Both teams are down to their final duelists, Yusei and Jean respectively. It's Jean's turn, and Yusei's deck is completely empty. Simply ''doing nothing and passing his turn'' would cause Yusei an automatic loss, shown Team 5D's (who, due to the double-loss elimination rule for the prelims, would ''not'' have been out of the competition) a great lesson in the effectiveness of a team building their decks to work together as opposed to the haphazard strategies theirs possessed, and given them all a great bit of character development....instead, Jean goes for the win by attacking one of Yusei's Defense Position monsters, who then gets a massive enough Defense Point boost that the backlash damage causes Jean to lose. Why does he attack? Because Yusei opened his eyes to how ''fun'' Dueling could be, lodging the Idiot Ball ''firmly'' in his chest.
** Given how often these Duels become life-and-death situations, it's amazing this wasn't a case of TooDumbToLive.

* Ciel Phantomhive is thrown the idiot ball in the second season of the ''Manga/BlackButler'' anime, when he doesn't question why Soma knows him and Ciel himself doesn't remember him. Instead of wondering about this also, Sebastian answers with "Foreigners are difficult to understand."
* ''Anime/PuellaMagiMadokaMagica'':
** Kyoko gets more of an Optimism Ball that works ''too'' well. She believes [[WeaselMascot Kyuubey]] that [[spoiler: Sayaka could be turned back from a witch, despite the fact that Kyuubey admitted to setting up the whole thing]]. She doesn't ask Homura, who has known about the whole system from the start, if he's [[YouDidntAsk withholding information]]. Finally, she brings Madoka (who is completely defenseless) to the fight, while Kyouko herself has a dimmed Soul Gem from overuse of magic. [[spoiler: It ends with a SuicideAttack, per Kyuubey's BatmanGambit.]]
** There's also the scene where Madoka [[spoiler:throws Sayaka's Soul Gem off a bridge]]. Not the smartest move, though it can be a little understandable since the girl was [[BreakTheCutie quite the emotional wreck already]]... but even worse is how Homura is nearby, knows [[spoiler:from experience]] how bad that sort of thing can turn out, and makes no real effort to stop it until it's too late. [[SarcasmMode What,]] [[TimeStandsStill did she not have enough time?]]
*** She may have allowed this to happen on purpose, so that Madoka [[spoiler:would learn how literal the name [[SoulJar "Soul Gem"]] is, and]] would be less likely to want to become a magical girl.
** ''Anime/PuellaMagiMadokaMagicaTheMovieRebellion'' reveals that Homura made a big mistake in the finale of the main series: [[spoiler:her telling Kyubey about Madoka and her wish allowed him to kick-start the plot of the movie.]]
* In one episode of ''Anime/TheBigO'', Roger chased Allen Gabriel onto an abandoned train in an empty train station, despite knowing beforehand that he himself is unarmed and that Allen Gabriel loves to kill people. Angel even lampshades what a dumb move this is.

* In Thunderbirds 2086 (not the puppet version), vetted astronaut and spaceship pilot, Captain Kallan James, in Episode 6 "Sunburn" actually asks "What's a ramjet?"
* ''Manga/{{Btooom}}'':
** The first episode. Okay, so the protagonist is a top-ranked player in this online game where you try to blow up your opponents with bombs. Then he suddenly finds himself on an island with a bag of things that look just like the bombs in the game, but he doesn't recognize them; he picks one up, presses a button on it, and a timer starts counting down. He still doesn't get it, but he "has a bad feeling" and throws the thing away just before it explodes.
** He now realizes that they are bombs, but ''he still doesn't know how to use them''. After letting a random bomb-throwing psycho chase him halfway around the island, he decides to fight back by throwing a bomb...without pressing the button. After the bomb fails to explode, he has the Shocking Realization (complete with ViewersAreGoldfish flashback to three minutes ago) that you have to press the button first! So he tries it that way, and it goes off too late. After a few minutes of screwing around incompetently, he has ''another'' Shocking Realization and flashback revealing that the numbers counting down were probably a timer! Eventually, he drops the Ball by tricking the nutjob chasing him into [[SomebodySetUpUsTheBomb standing on top of a bomb]]. About time, Mr. Expert Gamer.
* ''Manga/{{Claymore}}'': Teresa is antagonized by a group of bandits who know she's extremely powerful (they just don't realize [[StoryBreakerPower how far]] the "extremely" goes with her) but [[ThouShaltNotKill strictly forbidden from taking human lives]], but lets them go free and ([[AnArmAndALeg almost]]) completely undamaged, until they, being [[RapePillageAndBurn exactly]] the [[KickTheDog type]] of cruel assholes one would expect bandits to be, eventually provoke her into breaking that rule by torturing her protege. As far as anyone knows, AintNoRule about incapacitating them nonlethally, and bringing in humans who are willing to kill to protect their families from bandits to do what she isn't allowed to. Later on, when her erstwhile comrades are hunting her, she decides to kill Priscilla because she has the potential to challenge her in the future, and fails to do so several times despite every opportunity.

* ''Manga/AssassinationClassroom'':
** The Island arc is centered aroud Class E's assassination attempt on the titular vacation island. Everyone has lots of fun during the day, including Koro-Sensei, who gets so sunburned he becomes charred black. Fortunately, he has a "molt the skin" technique that can be used once per month and is usually used to leave a decoy. Too bad it uses quite a lot of energy, enough to slow him down... and that Koro-Sensei promised to let the students prepare an assassination attempt that very night... and that [[spoiler:he also promised to let them shoot 7 tentacles, which, just by itself, reduces his speed to a '''1/16th''' of his normal speed of Mach 20]].
** Chairman/Principal Asano has grabbed this and the VillainBall hard in regards to his treatment of Class E. Beating down the confidence of the only people in a legitimate position to end a world ending threat that will destroy ALL LIFE on the planet within a year is a terrible idea. If they fail due to, say a lack of confidence in their own abilities thanks to a systematic destruction, then he's equally culpable for the destruction of the human race in order to preserve his ideals as a teacher which favors grades over individuals. Worse, if they succeed? Then a phenomenally rich, highest quality assassin who has the favor of every government on the planet, the assistance of several of the worlds best assassins and an overtly obvious reason to HATE the principal for making their junior highschool years a living hell, has every reason to ruin/kill him with every resource available to them and basically no one to tell them not to. Anyone with real authority knows they saved the world, right?

* ''Manga/FairyTail'': Zigzagged in the [[WarArc Alvarez arc]], as Zeref seeks to obtain Fairy Heart, a source of infinite magic power within Mavis. When Mavis gets captured and hopes for his help during its extraction, he's reluctant about the pain she'll suffer but otherwise dead-set on his goal, forcing her to escape from her own guild at the nearest opportunity. However, the final strategy she comes up with for beating Zeref during the final mass melee between Fairy Tail and their allies against Alvarez has her going back because it requires her to profess her love to him (using the power of her own Curse of Contradictions to kill him despite his immortality as his nearly did to her so long ago), which she does during Natsu and Zeref's final battle to interrupt them, but Zeref reaffirms his own convictions despite his grievances and forcibly extracts Fairy Heart from her in less than a minute. ''However'', she's exonorated by the fact that she needed to be nearby when Natsu defeated Zeref, in order to have her and Zeref's love for each other lift their curse and allow them to [[TogetherInDeath die together]], while ensuring Natsu's victory by giving the book of E.N.D. to Lucy so that she could rewrite it and keep Zeref from killing Natsu (and him dying with Zeref in the end). In other words, the only way to win was to put herself in a position that would risk everything if it went wrong.

* ''Manga/CellsAtWorkAndFriends''' Chapter 3, "Ransomware," combines this with OutOfContextEavesdropping: Killer T's underlings find his broken cell phone, see or overhear bits of information, and come to the least reasonable conclusions possible, going so far as to conclude that he had a girlfriend and ''killed her''.
* In an episode of ''Anime/LittleWitchAcademia2017'', Akko and Amanda successfully infitrate a rival school known for anti-magic sentiment in a world where magic is on the decline, therefore their supply of magfic grows weaker the further away they are from Luna Nova. Yet Amanda still decides to expose herself by casting a spell on a student that predictably fails. The Story attempts to justify this by stating that Amanda wished to be expelled from Luna Nova, but this act placed both of them and their mission at great unnecessary risk.

* ''Anime/CodeGeass'':

** In [[Anime/FullmetalAlchemist the anime]], Greed goes full-armor when it's serious business. Any other time, he's still armored below the skin, as Izumi can attest to. "So, how many fingers did you break when you hit me just now?"

** A rather frustrating example occurs in the Death 13 mini-arc of Part 3, where ''everyone'' carries the IdiotBall. Everyone except Kakyoin refuses to believe that a baby with fangs (the villain of that particular mini-arc) could be a stand user while Kakyoin (normally one of the calmer members of the group) resorts to hysterics to try and convince everyone. The frustrating part comes from the fact that they're normally ProperlyParanoid, immediately assuming that anything unusual happening is the result of an enemy stand. They've already encountered s stand-using orangutan, not to mention Polnareff could use his stand since infancy, so a stand-using baby should be considered.

* ''LightNovel/SpiceAndWolf'': So, Lawrence. You've got a harvest goddess as a travelling companion, who prides herself at being "Horo the Wise" and being far cleverer than you give her credit for. You've already been called out for keeping secrets from her, and you had previously flubbed your [[TabletopGame/DungeonsAndDragons Insight check]] to pick up on her mood when you suggested you just [[spoiler: drop her off at the nearest town instead of going all the way to Yoitsu with her]]. Was it really such a good idea to [[spoiler: leave her with the letter that says her hometown is probably gone]], just because you assume she can't read?
** He didn't just assume - she ''told'' him she couldn't read. And she did it probably so she could play some kind of trick on him, while he kept a secret to spare her feelings. Their fight was a result of mutual miscommunication.

* In an episode of ''Anime/LittleWitchAcademia'', Akko and Amanda successfully infitrate a rival school known for anti-magic sentiment in a world where magic is on the decline, therefore their supply of magfic grows weaker the further away they are from Luna Nova. Yet Amanda still decides to expose herself by casting a spell on a student that predictably fails. The Story attempts to justify this by stating that Amanda wished to be expelled from Luna Nova, but this act placed both of them and their mission at great unnecessary risk.

** When Jeremiah recieves his [[AntiMagic Geass Canceller]], he tests it in a populated area without checking his surroundings. [[spoiler: This restores Shirley's memories, which then leads to her death the following episode and most of the above moments. The CompilationMovie changes this by having him warn Shirley not to get involved any further]].

*** After taking over the school during the finale of the first season [[spoiler:Lelouch didn't order the Black Knights to make sure the students -including his own sister- were guarded 100% of the time. After Ohgi is shot, the Black Knights leave them unguarded, most of the students take advantage of this to go help Suzaku, and V.V just waltzes on in and picks Nunners up]]. This makes Lelouch leave the Black Knights and causes the failure of the rebellion, leading to the capture of nearly the entire rebel force.