No protagonist is perfect. Every man, woman, [[KidHero child]], or [[AmbiguousGender person of ambiguous or nonstandard gender]] brings their own unique flaws and difficulties to their role in a story. Often stories will be about a protagonist's struggles to overcome these flaws. However, whether they succeed or fail, many of them will experience at least one Moment of Weakness. That instant in which their emotions or the stress of a situation goes past critical and causes a thoughtless reaction that they would ''never'' have if they were thinking clearly.

A Moment of Weakness can come and go, but will usually be recognized very quickly by the perpetrating protagonist. The typical response is usually one of two extremes. Either they'll wonder with horror "MyGodWhatHaveIDone" and try to [[TheAtoner atone]] [[RedemptionQuest for it]] or it will be the [[StartOfDarkness first step]] in a [[JumpingOffTheSlipperySlope running jump off the slippery slope]]. On occasion, you can even get someone who [[IgnoredEpiphany realizes the horror of their action, but not have that be enough to stop the leap.]]

To mitigate the potentially subjective nature of this trope: A Moment of Weakness is a single moment in which a character's emotions or stress levels run so high that they act contrary to their usual nature. This action almost always causes damage of some kind, most commonly to someone ''or'' something the protagonist truly cares about. This is one cause of OOCIsSeriousBusiness. Do not be surprised if an OhCrap follows.

It is not necessarily something that the character will look back on as MyGreatestFailure after the fact, but chances are that they definitely will be thinking of and agonizing over it as one of their more serious personal mistakes.

See MyGodWhatHaveIDone for more long-term examples and StartOfDarkness when the Moment of Weakness sends them the other way. If a rash action during such a moment leads to tragedy, see ATragedyOfImpulsiveness. Can potentially result in InsultFriendlyFire or KickTheMoralityPet. Compare InVinoVeritas, when this sort of thing can happen due to drunkenness. Also compare LetThemDie for when a normally heroic character becomes so enraged by a certain race or person that they lose all mercy towards them once their breaking point is reached.

[[AC:{{Anime}} & {{Manga}}]]
* [[{{Anime/CodeGeass}} Lelouch]] [[PrideBeforeAFall boasted]] that if he had to abandon his conscience to exact revenge, he'd discard it [[{{Hypocrite}} mere minutes before abandoning the people who were relying on him]] to go search for his little sister during the 1st Assault on the Tokyo Settlement (quite literally as soon as he started it).
* ''Manga/{{Saki}}'''s Kunihiro Hajime gave in to the urge to use sleight of hand to win a Mahjong tournament in grade school. Even into high school this act haunts her, undermining her confidence to play without doing so. This is the reason she's ChainedByFashion.
* ''Manga/BitterVirgin'':
** Daisuke found himself falling for Hinako. But when she obliviously gives him a JustFriends line, he angrily blurts out that he knows her [[AbusiveParents dark secrets]]. He gets lucky that Hinako wasn't actually listening to him at that moment but is horribly ashamed of himself afterward.
** Same with his childhood friend Yuzu, she accidentally overhears Hinako's dark secret. At first she is willing to keep it to herself but after hearing that Daisuke has already confessed to her, she blurts it out. She feels utterly horrified at herself when she discovers that not only is Hinako right behind her, but that Daisuke already knew.
* Ling in ''Manga/FullmetalAlchemist'' knowingly makes a DealWithTheDevil and allows himself to become the new Greed because of his obsession with gaining immortality. It overlaps with AnOfferYouCantRefuse because Ling would have died otherwise and [[spoiler: Greed later did a HeelFaceTurn, so that it ultimately wasn't a bad decision.]]
* During the Water Seven arc of ''OnePiece'', while having a heated argument with Usopp, Luffy blurted out that if Usopp didn't like the way he did things then he should just leave the crew. Sanji immediately stepped in to shut Luffy up, and Luffy apologized as soon as he realized what he'd said. But the damage had been done, Usopp took Luffy at his word, and (temporarily) left the crew.
* Inverted in ''{{Nichijou}}'' when Yuko throws a compliment to Mio while the two are having a fierce (read: MundaneMadeAwesome) argument, which leads to the whole thing defusing.
* Kyubey in ''Anime/PuellaMagiMadokaMagica'' is consistently shown trying to take advantage of such moments to score a Magical Girl contract. This is, in fact, how he recruited Mami and Sayaka.
* ''Anime/YuGiOh'': In the filler Doma arc, Yami does this when he faces off against Raphael for the first time and ends up getting the Orichalcos card after Raphael plays a card that forces them to switch each others hands. As Raphael repeatedly chips away at Yugi's lifepoints and backs him into a corner. Yami, against Yugi's protests, play the Orichalcos card and while it gives him an advantage, he constantly sacrifices his monsters to do so. This leads to falling right into Raphael's tactics and losing both the duel and Yugi's soul who went in his place as the seal only needed one of them. Needless to say Yami has a HeroicBSOD for awhile after that.
* Similarly, Aichi Sendou in ''Anime/CardfightVanguard'' has his following a BreakTheCutie incident revolving around Kai walking out on Team Q4 [[spoiler: due to Aichi inadvertantly using [[PsychicPowers Psyqualia.]]]] Kai has no idea how to stop it and, as Aichi's been working to become strong enough for Kai to acknowledge him, takes himself out of the picture. That plays right into [[TheCorrupter Ren's]] hands, who hands Aichi [[spoiler: a Shadow Paladin deck, which Aichi can feel the power of due to his ability; resulting in him tossing away the Royal Paladin deck hs spent years building, including the Blaster Blade that Kai gave him.]] For several episodes, Aichi becomes [[spoiler: DrunkOnTheDarkSide and uses tactics that sacrifice his allies, all in the name of his desperation to become stronger quickly]] - the opposite of his previous and something Aichi would never ordinarily do.

* This is the reasoning [[WordOfGod Dan Slott]] gave as to why Doc Ock was the "superior" one during his BattleInTheCenterOfTheMind with Peter Parker in ''ComicBook/SuperiorSpiderMan - Peter suffered a Moment of Weakness when he tried to stop Ock from using a device to save a girl that would end up finding him. Octavius is disgusted and uses that justification to [[spoiler:erase Peter from his mind]].
* In the last arc of ''ComicBook/{{Runaways}}'', Chase, having lost his beloved Old Lace, hits his moment of weakness and threatens to break every bone in Klara's body because she won't stop crying, and thus comes dangerously close to becoming an abuser like his old man. This in turn leads to a moment of weakness from Nico, who uses magic to force Klara to stop crying, because she doesn't want to stand up to Chase. Molly, whose own parents used to use their powers in similar fashion, [[WhatTheHellHero is NOT pleased by this]]...

[[AC: Fan Fic]]
* In ''FanFic/MegaManDefenderOfTheHumanRace'', Mega has one in episode 8 when he presses Wily's BerserkButton while trying to negotiate with him and Drill Man; he regrets it almost immediately.
* In the ''My Little Pony: Friendship is Magic'' fanfic ''Fanfic/ATasteOfTheGoodLife'', Scootaloo unexpectedly reunites with her mother, Ebby, whom she wants ''nothing'' to do with due to her having been an emotionally abusive alcoholic. Ebby continually pleads to reconcile, even going so far as to bring in Foal Protective Services. When Scootaloo runs away, Ebby pursues her and winds up hanging from a cliff. Scootaloo, absolutely desperate to have her mother out of her life forever, [[spoiler:flat-out refuses to try and help her, leaving her to her fate]]. Scootaloo soon realizes she went too far and her mother ([[spoiler:who was rescued anyway]]) realizes just ''how'' much she's hurt her daughter. This leads to a slow but genuine reconciliation.

* In ''Franchise/StarWars [[Film/AttackOfTheClones Episode II: Attack of the Clones]],'' Anakin Skywalker was perfectly content to sneak around the Sand Peoples' camp and not start a fight up until his mother died in his arms. His rage at that moment prompted him to murder every Sand Person there. He felt guilt over it afterward, but it didn't stop his fall to the Dark Side. [[FromBadToWorse It only got worse from there]].
* In ''Film/EndOfDays'', Jericho's best friend betrays him and makes a DealWithTheDevil because "it's amazing what you'll agree to when you're on fire." Especially galling since the Devil was the one who set him on fire in the first place. Near the end he can't bring himself to betray Jericho a second time, and the Devil revokes their deal by setting him on fire again.
* Carl Fredricksen in ''WesternAnimation/{{Up}}'' suffers two of these. The first at the beginning of the film. In a panic over his mailbox being knocked over, he hits a construction worker with his cane, getting him branded a public menace. The second is near the climax when [[BigBad Charles Muntz]] threatens to set fire to his house. He drops everything else, including protecting the MacGuffin bird, to put the fire out and snaps at Dug and Russel when the latter [[WhatTheHellHero calls him out]].
* In ''Disney/BigHero6'', Hiro discovers the identity of Yokai and, realizing [[spoiler:his brother died in vain]], tears out Baymax's healthcare chip to have him [[spoiler:kill Yokai for him]]. It is when his teammates stop him and him discovering his brother's true intentions for Baymax is that helps him see the error is his ways.

[[AC: {{Literature}}]]
* In ''Literature/TheDresdenFiles'' book ''Literature/WhiteNight'' Harry is forced to acknowledge the steadily growing influence of Lash after he loses his cool and destroys part of a building with his magic. Something the nature of Dresden-verse magic would make impossible unless Harry really ''believed'' in what he was doing. One of the book's villains, the Skavis, specialized in provoking and manipulating Moments of Weakness to make his victims commit suicide.
* In the ''[[Literature/ThePendragonAdventure Pendragon]]'' series Bobby snaps and pushes a bad guy out of a helicopter. [[BigBad Saint Dane]] had wanted him to do it, and told him to, and he knew it would end up making things worse, but he was just that angry.
* In the ''Literature/VorkosiganSaga'' novel ''Memory'' Miles covers up an assignment that was horribly botched because of health problems which he had also been keeping from his superiors. Although he's always breaking rules, up to this point it had been for the greater good; this time it was mostly selfish and he is dismissed from imperial service as a result. Later in the novel, when considering the villain, Miles notes that this could have been the point at which he did a FaceHeelTurn, but unlike the villain, he stopped himself.
* In ''Literature/HarryPotterAndTheDeathlyHallows'', it's revealed that it was exactly such a mistake that caused Severus Snape to forever destroy his friendship with the one person he cared for when [[spoiler:he called Lilly Potter (then Evans) a mudblood.]]
* In ''[[{{Mistborn}} Well Of Ascension]]'' , Vin gets frustrated by her inability to protect Elend and her general feelings of inadequacy at everything except killing and decides to [[spoiler: attack Cett and slaughter everyone who gets in her way]].
* Before Kayneth's assault on the Einzburns' castle in ''LightNovel/FateZero'', Irisviel is starting to wonder just how much she really knows Kiritsugu. The past few days has seen him return to his ColdSniper persona, in stark contrast to the loving father and doting husband she'd known for the last few years. As she's wondering, [[spoiler:he embraces her and, on the verge of tears, asks her if they can just forfeit the Grail War, rescue Ilya, and live together in peace]].
* In the first ''Literature/{{Safehold}}'' book, ''Off Armageddon Reef'', Merlin acts entirely without thinking when a group of children are attacked by the Safehold equivalent of a shark; in the process revealing a portion of his [[RidiculouslyHumanRobot more-than-human]] abilities to someone whose trust he needs and could easily view his abilities as demonic. Merlin only realizes this a few seconds after he's already committed to action. Only the fact it was a blatant act of ChronicHeroSyndrome that Merlin never considered ''not'' doing allows him to retain the trust he's earned.
* ''[[Literature/AMagesPower A Mage's Power]]'': Tasio has been waiting for Eric to have a particularly bad day, because only then would he ask for help. The Trickster needs him to do this so he can deliver the CallToAdventure and [[TrappedInAnotherWorld drop him in another world.]]

* The short-lived television series ''GVsE'' generally had villains who convinced people to make a DealWithTheDevil, and good guys getting them to break those deals at the cost of what they were given. One episode stands out, however, as the bad guy of the episode approached people on the verge of death from accidents and used these deals to save their lives.
* ''Series/BabylonFive'':
** Lennier at the end. In his case he [[TheAtoner pays penance]] for the rest of his life, apparently dying in the Telepath War.
** Delenn at the Earth-Minbari war.
** Sheridan while interrogating Mr Morden.

* Even [[{{Badass}} Commander Shepard]] from the ''Franchise/MassEffect'' series isn't immune to this, though his/her single (so far) MomentOfWeakness potentially happens in a very sheltered environment and doesn't have any lasting consequences: in the end of the ''[[{{DLC}} Lair of the Shadow Broker]]'' storyline, [[UndyingLoyalty Liara]] comes to visit Shepard and asks him/her how s/he is ''truly'' feeling rather than what s/he tells the crew. The Paragon answer to that is the first and only occasion the Commander expresses any doubt about his/her mission in the entire series (depending on whether this takes place before or after the SuicideMission, Shepard will refer to the latter or to the impending Reaper invasion). Also, this speaks volumes about Shepard and Liara's relationship (regardless of whether [[RomanceSidequest romance]] was pursued).
** S/he also shows it if you pick the renegade options (not really renegade but just different emotional responses) where [[IronWoobie Shepard]] both talks about just how hopeless his/her war against the Reapers seems and how exhausted s/he is from dealing with Cerberus, the Citadel Council who always treat him/her like s/he's lying or insane, [[KnightInSourArmor and of his/her closest friends shunning him/her because s/he's working with Cerberus.]]
** S/he has a ton of them in ''VideoGame/MassEffect3'' where s/he finally starts to crumble, physically and mentally, under the pressure of being the spearhead of a war effort against a [[NighInvulnerability nearly unstoppable]] [[HopelessWar enemy force.]] All of his/her friends constantly worry about him/her and do what they can to keep her from going completely past the DespairEventHorizon. S/he very nearly has a HeroicBSOD after the [[DarkestHour Fall of Thessia.]]
** One particularly notable one is during the assault on the Cerberus HQ, when Shepard finds a video describing how bad his/her body's condition was following his/her death at the beginning of ''2''. Almost completely absentmindedly, without even thinking about what they're in the middle of or the people around him/her, s/he goes into a brief existential crisis over whether or not s/he's the real Shepard or just an advanced VI programmed to think it's Shepard, talking more to him/herself than anyone else. It takes his/her TrueCompanions and possible LoveInterest reassuring him/her that they believe s/he is real to snap him/her out of it.
* In ''VideoGame/DragonAgeII'', any companion you bring into the Fade in the sidequest 'Night Terrors', no matter how high their friendship or rivalry score is, will fall for the demon's offer and attack you (except for Anders, who's immune due to Justice, and Sebastian, who refuses to go in the first place).
* VisualNovel/KatawaShoujo: Go on. You know you want [[spoiler: Misha]], don't you? She's right there. All you need to do is say "yes"...
* Sonic has a particularly nasty one in ''[[VideoGame/SonicBoom Sonic Boom: Rise of Lyric]]''. After warding a wave of robots outside of Lyric's Tomb, an even larger wave shows up. Whereas Knuckles, Amy and Tails move into place to face them, Sonic just sits there paralyzed; in his panic, he moves to open the door, with Amy telling him not to. Then Metal Sonic shows up, and Sonic caves, opening the tomb and leading everyone inside. Not only does this lead to [[NiceJobBreakingItHero Lyric getting loose]], but Sonic gets on the bad side of everyone watching: Amy, Knuckles, Tails, and even Shadow, who saw the whole thing from above.
-->'''Tails''': Uh... I don't think those doors were built to keep us out... [[SealedEvilInACan they were meant to keep]] '''[[OmnicidalManiac that]]''' [[SealedEvilInACan in]]!\\
'''Amy''': Let's get out of here! [[WhatTheHellHero Oh, wait I forgot.]] ''[[WhatTheHellHero We can't.]]''\\
'''Knuckles''': [[WhatTheHellHero Not cool, Sonic! You locked us in!]]\\
'''Sonic''': Locked us in? I was saving you!\\
'''Knuckles''': We didn't ''need'' saving!\\
'''Amy & Tails''': Yeah!\\
'''Shadow''': Saving the world? You? Don't make me laugh. You're weak! And you know what makes you weak? Your loyalty to your pathetic friends! You're not going through that portal... I'm going to show you just how weak you are!
* In her background, [[VideoGame/{{Touhou}} Fujiwara no Mokou]] followed a troupe of soldiers to the top of Mount Fuji when they were about to dispose of an ImmortalityInducer elixir. She kept on going after them as they fell one by one until only one, Iwasaka, remained. When he was about to dump the thing into the volcano, he received a divine message telling him not to, lest he trigger a permanent eruption. Mokou took advantage of the tired soldier and killed him, taking the elixir for herself. Centuries later, she still feels enormous guilt over killing Iwasaka.
* In ''VideoGame/TelepathTactics'', Emma does not take her reunion with [[DrillSergeantNasty Silithis Predat]] well. [[OOCIsSeriousBusiness In a departure from her normally reserved behavior]], she immediately assumes the worst of Silithis and insults her when Silithis tries to apologize for her past abuse. [[spoiler:This ends up working out well for her, as it allows Silithis to realize that she really was too hard on Emma. Emma later accepts the apology when Silithis tries again.]]

* ''Webcomic/TheOrderOfTheStick'', Varsuuvius made the decision to make a DealWithTheDevil (and Demon, and Daemon). V knew that dealing with infernals was a bad idea, and they even offered an alternate method where the elf would owe them nothing. However, at that point, V was trance-deprived, guilt ridden, and both pride and body were crushed by a dragon, who was minutes away from killing the elf's family. Varsuuvius, unable to admit defeat like the alternate method would require, makes the deal and takes a step towards TheDarkSide. The strip is even titled [[ "The Wrong Reasons"]] in reference to a prophecy that Varsuuvius would obtain ultimate power by saying the right four words at the right time for all the wrong reasons.
* In ''Webcomic/GunnerkriggCourt'', Antimony & Reynardine do this to each other. Annie tells Renard that he'd been used by someone he'd cared for when he kept badmouthing her father. He got back by revealing the real reason behind her mother's death.
* In ''Webcomic/{{Sinfest}}'', [[ after a Flashback]], [[ Fuchsia had a stabby episode]]. [[ Sometimes she just gets so angry at everything.]]

* In the first five minutes of ''WesternAnimation/BatmanBeyond'', an aging Bruce Wayne [[BatmanGrabsAGun is forced to pull a gun]] on a kidnapper who was beating him to death when his heart gives out during the battle. He retires from being Batman immediately afterwards.
** In "Out of the Past", Talia offers Bruce an opportunity to restore his youth using the Lazarus Pit. He resists the temptation, but changes his mind after he and an innocent bystander are nearly killed in a mugging he once could have handled easily. [[spoiler:It was a setup designed to trigger just that reaction.]]
* All of the protagonists have these in ''WesternAnimation/AvatarTheLastAirbender'':
** Aang can't let go of his love for Katara; this turns out to be quite the problem.
** Katara never forgave the Fire Nation for her mother's fate and [[spoiler: almost murders a man in a fit of vengeance.]]
** Poor Zuko. The worst one is mainly caused by Azula, as part of a BigScrewedUpFamily.
** When Ozai revealed his plan to [[spoiler:burn the Earth Kingdom to ashes]], Zuko didn't protest it ([[GenreSavvy because he remembered what happened the last time he did]]). That made Zuko realize that he had lost his courage, and that was the final push he needed to join Aang's side.
* ''WesternAnimation/TheLegendOfKorra'': Korra has a breakdown at the end of "''The Voice In The Night''". She makes a public challenge to fight [[BigBad Amon]] at an appointed time and place, and naively believes he'll play fair. Amon does eventually show up for the fight, [[CombatPragmatist except he brings a dozen armed henchmen with him.]] They ambush Korra, tie her up, and drag her off into the darkness where Amon makes it clear to her that the only reason he doesn't [[spoiler: remove her bending forever]] is because [[DangerouslyGenreSavvy that would turn her into a martyr]]. After they [[StealthHiBye take their leave]], Korra is left sobbing into her mentor Tenzin's chest.
* DoubleSubverted in the ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' episode "[[Recap/MyLittlePonyFriendshipIsMagicS2E5SisterhoovesSocial Sisterhooves Social]]." Throughout the first half, Rarity is actively trying not to blow her top at little sister Sweetie Belle's attempts at JustTryingToHelp. However, Sweetie Belle's frustration at Rarity not wanting to spend time with her eventually reaches a breaking point, prompting her to angrily disown Rarity as a sister, and Rarity finally loses her temper right back.
** In "[[Recap/MyLittlePonyFriendshipIsMagicS4E20ForWhomTheSweetieBelleToils For Whom the Sweetie Belle Toils]]," Sweetie Belle hits her RageBreakingPoint when she thinks Rarity deliberately upstaged her with costumes so good that the audience of the play she wrote, directed, and starred in found them more memorable than the play itself. In retaliation, she sabotages a headdress made for one of Rarity's most important clients. The episode focuses in getting her to realize her error and fix it before it's too late.