History NiceJobBreakingItHero / AnimeAndManga

* In episode one of ''ToAruMajutsuNoIndex'', Touma destroys Index's magically MadeOfIndestructium cloak to prove he has AntiMagic. This leaves her defenseless and she becomes grievously wounded later.
* In ''TheWorldGodOnlyKnows'' manga, [[spoiler: Haqua released Fiore out of mercy when Fiore showed "evidence" that she is innocent. Later on, Nora tries capturing her but both Haqua and Nora were restrained. So yeah, Haqua, maybe you should have followed Keima's instructions. Nice job breaking it, Haqua.]]

* Frequently implied to occur whenever the ''DirtyPair'' are on the job (it's the reason for their EmbarrassingNickname), but one OVA episode spells it out plainly. The Angels are investigating the mysterious deaths of several hundred mining employees on a planet run as a religious colony; they find that the religion's leadership has evolved into a murdering cult that, with the help of a ring of weather satellites, is capable of calling down Sodom-and-Gomorrah-style devastation down in a specific location. After they destroy the cult's station in orbit, they assume correctly that the cult's reign of terror is ended. Unfortunately, the space station was also the control for the weather satellites, and the weather satellites ''weren't'' just used for destructive purposes; the Angels look down from orbit and see about nineteen hurricanes beginning to form, with no weather-control system left to prevent them...

* In ''JigokuShojo Mitsuganae'', Mikage is able to sense when someone nearby may soon be a client of Enma Ai. In one episode, she stops one such person and urges her not to use the Hotline to Hell... which she had ''never heard of until then''. Smooth.

* The one moment like this in ''[[DragonBall Dragon Ball Z]]'' is when Krillin fell in love with Android 18, and prevented her being self-destructed, resulting in her absorption by Cell, creating Perfect Cell.
** Hey, now, Vegeta was just as guilty, not killing Cell when he had the chance and instead HELPING him absorb Android 18. So they're both at fault.
*** Gohan also had a chance to kill Perfect Cell and didn't because ''[[RevengeBeforeReason he didn't feel Cell had suffered enough]]''. Shortly after regenerating, Cell used his self-destructing attack, leading to Goku's second death.
*** Piccolo managed to pull one of these directly with Buu. He was attempting to buy more time for Goten and Trunks to prepare by pointing out that Buu had promised not to fight them until he'd killed everyone on Earth. Buu acknowledged this... by [[KillEmAll killing every person on Earth]] except for the main cast [[CompleteMonster with one attack]].
** And of course, if you count OVAs, Goku's SenselessSacrifice with Perfect Cell freed Bojack from imprisonment within King Kai's planet.
** Then there was the Buu saga, where the actions of the heroes contributed to the overall mayhem
*** The Supreme Kai, in allowing Gohan to be drained of his energy, planned to track down Babidi... except he vastly underestimated how much of the necessary energy would be extracted.
*** The battle between Vegeta and Goku produced so much power it accelerated Buu's awakening even more.
*** In an effort to make the battle with Super Buu more dramatic, Gotenks [[InvokedTrope acts like]] he's completely outmatched and that he's going to be defeated as a [[MyNameIsInigoMontoya setup]] for his [[SuperForm Super Saiyan 3 transformation]], but Piccolo takes him seriously and destroys the door to the Hyperbolic Time Chamber and leaving the three trapped forever. However, the prospect of having no candy triggers Buu into an UnstoppableRage, causing him to scream so loud he [[BeyondTheImpossible tears through the fabric of time and space]] and is able to escape to the regular dimension on Kami's Lookout, where he [[KillEmAll kills everyone there]], including [[ItMakesSenseInContext one of Gotenks' mothers]].
*** Perhaps the biggest Nice Job moment was when Goku and Vegeta successfully rescue their sons and Piccolo from within Super Buu, thinking it would reduce his power level. Their efforts caused the monster to revert into Kid Buu, who was almost as powerful as Super Buu but even ''more'' [[KidsAreCruel psychopathic]].
** How about ''[[DragonBallGT GT]]''? It turns out that the heroes can only make one wish with the Dragon Balls for only a year. Thanks to overusing it from Dragon Ball to Dragon Ball Z, that's how the Shadow Dragons came into existence.

* Seems to be happening in ''MahouSenseiNegima''. All of Ala Alba went to the Magical World, including the [[spoiler: unbeknownst-to-them-Princess Asuna.]] Asuna is then kidnapped by Fate and the Cosmo Entelecheia remnant, who do... ''something very ominous'' relating to her AntiMagic powers. It hasn't completely panned out yet, but [[WildMassGuessing the going theory]] is that by bringing the Princess to where the bad guys can get her, ''they directly caused the revival of the BigBad''. Good going.
** Negi also seems to have majorly screwed up his parents's plans. It seems that they stuck him in Wales so that he could live out his life in safety, hidden from [[spoiler: [[GovernmentConspiracy the Megalomesembrian Senate]],]] and save for [[DoomedHometown one isolated incident]], it worked fairly well. Until he blew it by diving right back to all of the crap that everybody was trying to protect him from. Nice job.
** Wasn't the plan less of "let him live safely hidden" and more of "Hide him until he is ready"? If his father's remaining comrades really want him to be [[LockedOutOfTheLoop let out of the loop]], they wouldn't have let him leave Wales, teach a class full of [[FantasyKitchenSink unnatural students]] in an ElaborateUniversityHigh (filled with many Mages secretly living with the muggles), study martial arts from Ku Fei, learn advanced magic ([[MagicKnight and combat]]) training from [[SealedBadassInACan Evangeline]], enter a Martial Arts Tournament, and more importantly, go to the Magic World to find clues of his parents despite all the dangers present.

** He makes a very similar (and also understandable) mistake later: [[spoiler:While fighting a Level 4 Akuma, in order to trap it, he deliberately makes himself a target, then summons his sword from across the room, impaling both the Level 4 and himself. This would have worked fine if it wasn't for the [[TomatoInTheMirror little snag]] that he's the host for the Fourteenth Noah. Even the Akuma looked terrified out of its mind before he managed to suppress it.]] This is why this series has its own HighOctaneNightmareFuel subpage.

** We saw this yet again when [[spoiler: [[TheStarscream Gin]] [[AndTheFandomRejoiced revealed his hundred-year plot to kill Aizen]] [[CrowningMomentOfAwesome in epic fashion.]] [[GambitPileup ...Then we find out that it was part of Aizen's plan]] [[OneWingedAngel to get even stronger.]]]] Damn PlotCoupon.

** Suzaku is just as complicit in the latter, as [[spoiler:he was strongly advised by not only Cecile and Lloyd, but also Kallen herself, to retreat. Suzaku chose to remain there and suffer death, which is what led to his Geass command activating and driving him to fire off FLEIJA]].

* In ''YuYuHakusho'', the Chapter Black saga, Yusuke allowed [[BigBad Shinobu Sensui]] to fully power up so they could have a good battle. This ended up getting him killed. Dangit, Yusuke, you made Kuwabara cry again!

* While they can't be fully considered "Heroes" the Marines in ''OnePiece'' cause this following [[spoiler: The Whitebeard War. Their long, elaborate plan to kill Whitebeard worked, and they also killed off the son of the Pirate King (Ace). The only problem is that in doing so, they horribly screwed up the power balance of the New World, causing several towns to get overrun by pirates. Also, since Whitebeard confirmed that One Piece existed with his dying breath, the piracy rates have practically DOUBLED. To make matters worse, Blackbeard managed to free some of the worse criminals in the history of the world, added them to his crew, and has now stolen Whitebeard's Devil Fruit, which is capable of causing untold carnage, before finally declaring war on the World Government. And to top it all off, the Elders decided to censor the escape of even more of the Level 6 prisoners, meaning they can do whatever the hell they want. So basically, they wound up screwing up the Entire World thanks to a horribly short sighted plan. BRAVO. [[SlowClap *Clap* *Clap* *Clap*]] ]]

*** Gohan also had a chance to kill Perfect Cell and didn't because he didn't feel Cell ''had suffered enough''. Shortly after regenerating, Cell used his self-destructing attack, leading to Goku's second death.

* In the ''[[FullmetalAlchemist Fullmetal Alchemist]]'' movie, ''The Conqueror of Shamballa'', [[spoiler:Al opens the gate between his world and ours as the Thule Society does on our side, in an attempt to rescue his brother Ed. Though Ed escapes, it also allows the Thule Society to launch a full scale war on Amestris, and nearly destroys the capitol city]]

*** Perhaps the biggest Nice Job moment was when Goku and Vegeta successfully rescue their sons and Piccolo from within Super Buu, thinking it would reduce his power level. Their efforts caused the monster to revert into Kid Buu, who was almost as powerful as Super Buu but even ''more'' [[KidsAreCruel psychpathic]].

*** Perhaps the biggest Nice Job moment was when Goku and Vegeta successfully rescue their sons and Piccolo from within Super Buu, thinking it would reduce his power level. Their efforts caused the monster to revert into Kid Buu, who was almost as powerful as Super Buu but even ''more'' [[KidsAreCruel psychotic]].

** How about ''[[DragonBallGT GT]]''? [[spoiler:It turns out that the heroes can only make one wish with the Dragon Balls for only a year. Thanks to making wishes for many years, that's how the Shadow Dragons came into existence]].

** Not to mention Madoka nearly killed [[spoiler: Sayaka]] by throwing her soul gem down the bridge, and Homura had to clean up after her mess.

* ''MagicKnightRayearth''. Save the princess, kill her kidnapper, SaveBothWorlds, right? Uh... [[spoiler: not when he was RESCUING the princess from a life as a BarrierMaiden that can't even think for herself, and, because she knew she was stuck in that role and her happiness and self-fulfillment could kill the whole kingdom, she sent the Magic Knights as unknowing {{Laser Guided Tykebomb}}s to kill HER, not him.]] After the resulting psychological trauma of TheReveal [[spoiler: and being forced to kill the both of them, that leaves the place without a BarrierMaiden, and guess who has to choose between letting the kingdom suffer and dooming one person to a life of misery? No wonder Hikaru decides to MakeABetterWorld instead.]]

* In {{Tsukihime}}, if it weren't for Shiki "killing" Arcueid, Arcueid could effortlessly defeat all her enemies and Shiki himself wouldn't be dragged into her business.

* While they can't be fully considered "Heroes" the Marines in OnePiece cause this following [[spoiler: The Whitebeard War. Their long, elaborate plan to kill Whitebeard worked, and they also killed off the son of the Pirate King (Ace). The only problem is that in doing so, they horribly screwed up the power balance of the New World, causing several towns to get overrun by pirates. Also, since Whitebeard confirmed that One Piece existed with his dying breath, the piracy rates have practically DOUBLED. To make matters worse, Blackbeard managed to free some of the worse criminals in the history of the world, added them to his crew, and has now stolen Whitebeard's Devil Fruit, which is capable of causing untold carnage, before finally declaring war on the World Government. And to top it all off, the Elders decided to censor the escape of even more of the Level 6 prisoners, meaning they can do whatever the hell they want. So basically, they wound up screwing up the Entire World thanks to a horribly short sighted plan. BRAVO. [[SlowClap *Clap* *Clap* *Clap*]] ]]

* In ((Gundam SEED)) Athrun manages to blow up his mobile suit not once, but TWICE, and then a third time in the sequel series, but not on purpose... Though Lunamaria is also pretty good at getting herself blown up.

* In the Ark arc of ''[=~D.Gray-Man~=]'', WideEyedIdealist [[TheMessiah Allen Walker]] is facing off against Tyki Mikk. During the fight, Tyki accidentally pushes him into a ShonenUpgrade, and his EmpathicWeapon turns into [[spoiler:a [[{{BFS}} really big sword]]]] that can't damage humans- only Akuma and Noah. Tyki had been relying on Allen's [[ThouShaltNotKill reluctance to kill another human]], so he was a bit surprised when Allen [[spoiler:stabbed him right through the chest in an attempt to remove the Noah from him.]] It seems to have worked for a while... but then it turns out that [[spoiler:all Allen managed was to wake it up, and Tyki goes BodyHorror OneWingedAngel.]] [[OhCrap Woops]].

* The whole story of ''MagicalGirlLyricalNanoha A's''. [[GottaCatchEmAll "Let's save our mistress by filling this Book of Darkness!"]] Well, it's not [[LaserGuidedAmnesia really their]] [[XanatosGambit fault anyway]], but nevertheless [[WeCouldHaveAvoidedAllThis they made quite a mess]].

* In ''GundamWing'', the Gundam Pilots hear about a meeting of the Alliance's leadership and attack, hoping to free the colonies in one fell swoop. Unfortunately, Treize Khushrenada [[XanatosGambit had it all planned out]], and sets things up so the main character kills the Alliance members who were advocating peace, making the Gundam Pilots look like villains while giving his organization the opportunity to sweep in and take over. ([[NeverHeardThatOneBefore And yes, we know the guy responsible is named Heero]]. [[NoJustNo Please resist the urge to make]] [[IncrediblyLamePun any puns]].)

* The sum result of the [[spoiler: Hueco Mundo arc]] in ''{{Bleach}}''. [[spoiler: Orihime left to save her friends, who went after her to save her, who were followed by half of the remaining captains (who, despite at least two of them having their own agendas, did save everyone's favorite group of idiots) and their subordinates... only to find out that that was [[BigBad Aizen's]] XanatosGambit all along when re-kidnaps the poor BarrierMaiden, closes the Gargantua's that the shinigami had used to get to HM (effectively trapping them all), and merrily skips off to have his way with Karakura Town. And let's not forget how not only did Aizen only find out about Orihime's RealityWarper powers because she tried to help her friends, but that Urahara knew he might go after her and tried to stop her from fighting afterwards ([[StayInTheKitchen in a way that even he admitted was a mistake]]), only for Rukia to rebuild her confidence and take her away for training, which ends up leading her to be fantastically exposed when [[TheDragon Ulquiorra]] stops her while she was trying to return to the human world to fight alongside of her friends.]] Give yourselves a pat on the back, heroes. You really earned it.