History MyGodWhatHaveIDone / AnimeAndManga

** Lelouch has a DelayedReaction version of this when the memory of his murder of [[spoiler:his half-brother Clovis]] from the previous episode causes him to vomit (you see the bathroom sink water running indicating he did get sick).

** Suzaku also has one of these [[spoiler: when he realizes he's JumpingOffTheSlipperySlope by trying to drug Kallen with Refrain to get information out of her]].

* ''Manhua/InfiniteApostlesAndTwelveWarGirls'': Lilith is horrified that she tried to stop Elsa from eloping with Yu after hearing what the pre-arranged marriage partner had in mind for her daughter.

* ''Manhua/RetiredHeroes'': An adventurer retired from being a soldier when they found a group of demons masquerading as merchants, and slaughtered them all--including the children. He was so horrified that he resigned and started WalkingTheEarth. It gets worse when his partner (who is also a demon, though he didn't know at the time) points out that the demons weren't masquerading as merchants to spy on humans; they ''were'' merchants, who accepted the risk of being killed if they were discovered because it was still the safest way to make money.

* In ''Anime/{{Monster}}'', after seeing all of the death and despair caused by Johan Liebert, Franz Bonaparta breaks down completely, feeling guilt for being the man who made Johan into the monster that he is.

** Ichikawa has this in Karte 43/Episode 9 when Yamada confronts him about [[spoiler: avoiding her two days after a FakeOutMakeOut, assuming that she was using him as a tool throughout their relationship.]] Her starting to cry and wiping her tears off with a tissue pack he left for makes him realize that [[SheepInSheepsClothing he was more than wrong.]]
** Both of them have this in Karte 60 when [[spoiler: Ichikawa absentmindedly shows her a blurry picture of snow that he took the very moment he broke his arm during his family trip to Akita; Yamada previously confessed wanting to go there and he promised to take pictures of the scenery for her. Ichikawa immediately [[OhCrap realizes]] that [[GuiltComplex she would blame herself for his injury]] the moment he sees her horrified face.]]

** Both of them have this in Karte 60 when [[spoiler: Ichikawa shows her a blurry picture of snow that he took the very moment he broke his arm during his family trip to Akita; Yamada previously confessed wanting to go there and he promised to take pictures of the scenery for her. Ichikawa immediately realizes that [[GuiltComplex She blames herself for his injury]] the moment he sees her horrified face.]]

** Andreas Darlton gets one of these [[spoiler: after his hypnosis via Geass wears off and he realizes he just saved Zero by stabbing Cornelia's Quinn Roses in the back. He spends his last moment screaming for his princess as Zero obliterates him as "thanks".]]

* ''Anime/DigimonAdventure02'': It's discovered that BigBad Ken Ichijouji, definitely an EvilOverlord with a ZeroPercentApprovalRating, never knew Digimon were sentient, thinking the Digital World to be a very, ''very'' realistic [[VideoGameCrueltyPotential video game]]. He gives this line [[AndYouThoughtItWasAGame once he finds out he's done real harm]], and makes a HeelFaceTurn.
* With Chikara. When Oikawa was a kid, he was friends with Cody's dad whom both came in contact with the Digital World. Chikara has yet to know the Digital World was real and thought it was nonsense that he took the games away and tried to separate them, accidentally provoking Oikawa's obessession and unintentionally making him isolated, bitter and lonely, making him an easy prey for Myotismon's ghost. Chikara sorely regrets it once he saw the end result.
* ''Anime/DigimonFusion'': Much like Ken, Ewan Amano didn't realize Digimon were living creatures until his battle with Mikey. He also makes a HeelFaceTurn, though it takes until the sequel for him to [[spoiler: earn his partner back]].
* ''Anime/DigimonTamers'':
** Yamaki actually yells this under the dramatic and appropriately messed-up sky created by his program Juggernaut, an attempt to purge digital life from reality that instead results in a massive and highly dangerous breach between the worlds. Of course, this a fellow about whom the line, "Looks like your pal Yamaki ripped open the sky again," has been uttered. This of course leads to him being fired, and after a good sulk, he begins his HeelFaceTurn.
** [[BloodKnight Beelzemon]] spends a good deal of time wandering the Digital World listlessly, thinking back over his actions after [[spoiler: he kills Leomon and is later saved by Leomon's Tamer, Jeri]]. He's so disgusted by himself that he completely loses the will to fight and even to live, not even ''trying'' to fight back while a group of Chrysalismon beat him halfway to death. He (somewhat) snaps out of [[VillainousBSOD it]] when he finds out that Renamon and Rika risked their lives to find him, and, well...[[HeelFaceTurn I think you know]] [[TheAtoner where this is going]].
** Takato says this word for word after his anger at [[spoiler:Leomon's death]] gives normally innocent and friendly Guilmon a SuperpoweredEvilSide in Megidramon.
* ''Anime/DigimonFrontier'':
** Takuya's first use of his Beast Form results in him mindlessly trying to destroy everything in sight, including his ''terrified'' teammates. He eventually snaps out of it but still came within an inch of killing his surrogate little brother Tomoki and is promptly so frightened by this new power that it takes a full episode and Tomoki getting kidnapped for him to try using the Beast Form again.
** [[spoiler: Even while BrainwashedAndCrazy, Kouichi is still able to have this reaction when he nearly kills Kouji. This is strictly because of Takuya, who is having a bout of it himself since Kouji only got hurt because he was TakingTheBullet for Takuya, screaming Kouji's name and unfortunately it's not strong enough to snap him out of the brainwashing]].

* Endeavor has a big one in ''Manga/MyHeroAcademia'' when he realizes the villain Dabi is actually his oldest son Toya, and that his past as a jerkass AbusiveParent drove Toya to become an evil mass murderer.

* ''[[Series/{{Kikaider}} Android Kikaider: The Animation]]'' (not to be confused with the [[{{Toku}} live-action ancestor]] of the "Franchise/PowerRangers".) In the first episode, Jiro [[HenshinHero (the android)]] helps some kids get their toy airplane out of a tree by pushing the tree over. (He was in his "human" form at the time, and the kids thought they were enlisting his help to ''climb'' the tree.) After the the kids run away, [[MoodWhiplash any humor in this moment gets a kick in the nuts]] when Jiro realizes there was a bird's nest in the tree, and the eggs in it have been destroyed. In the English dub, he utters the trope verbatim.

* Doctor Marcoh from ''Manga/FullmetalAlchemist''. Now that he's gone and [[spoiler:made the damn Philosopher's Stone already]], he feels horrible about it. With good reason. Also, most of the protagonists in the Ishval arc. War suddenly doesn't seem so great anymore.

** In [[Anime/FullmetalAlchemist the 2003 anime version]], when Ed kills Greed, the first time he ''intentionally'' killed someone.
*** From the same continuity, Roy after [[spoiler:killing Winry's parents]]. He has a more stoic one after [[spoiler:killing Bradley/Pride]].

** And finally a third instance that sends him into even deeper despair after [[spoiler:he has [[ADateWithRosiePalms masturbated]] over a [[DudeShesLikeInAComa comatose]] [[LoveInterest Asuka]]]].

* ''LightNovel/FallingInLoveWithTheVillainess'': This is the king's reaction after his royal guard captain gives him a good TheReasonYouSuckSpeech after the catastrophe that was Vincent's execution, although he doesn't say it out loud.

* ''LightNovel/ArifuretaFromCommonplaceToWorldsStrongest'': Aiko is horrified when she learns that [[spoiler: the methane explosion that took down the Holy Church's cathedral went far beyond her intention of taking down the cathedral's barrier and killed everyone within in an instant.]]

* ''LightNovel/ACertainMagicalIndex''. After crossing the MoralEventHorizon and getting defeated by Touma, Accelerator notices that his selfish ideals to get his own peace have twisted his mind and taken more than 10,000 innocent people's lives. He tries to redeem himself by saving people for first time in his life but... BANG! he gets a bullet in the brain. [[RedemptionEarnsLife He survived but at the cost of most of his powers]].

* Happens to Caster in ''LightNovel/FateZero'' when he sees the light from Saber's Excalibur. It reminds him of the joy he felt when he was with his beloved Jeanne and the latter's purity, and he manages to muster out "What... have... I..." before being killed.

* In ''LightNovel/HighSchoolDXD'', Lord Zeoticus Gremory has a moment upon realizing that he was forcing his beliefs onto his daughter Rias, such as organizing an ArrangedMarriage to Riser Phenex as opposed to letting Rias choose a husband for herself when Riser was really a major {{jerkass}} and Rias is against the marriage proposal. Zeoticus's son Sirzechs helps Rias's LoveInterest Issei Hyoudou defeat Riser in an EngagementChallenge; Zeoticus apologizes to Lord Phenex for her cancelling the engagement and he is EasilyForgiven. It's even lampshaded by Zeoticus's wife Venelana in Volume 5.

* In ''LightNovel/InvadersOfTheRokujyouma'', Koutarou argues with Sanae and causes her to run away. While looking for her, he runs into Harumi and tells her what he said to Sanae. He's horrified when Harumi explains just how hurtful his comments were, and steps up his attempts to find Sanae.

* ''LightNovel/MyNextLifeAsAVillainessAllRoutesLeadToDoom'':

* ''LightNovel/AnObservationLogOfMyFianceeWhoCallsHerselfAVillainess'':

* ''LightNovel/SwordArtOnline'': Asuna's father gets such a moment upon the reveal that Nobuyuki Sugou, for whom he had set up an ArrangedMarriage with Asuna and [[HorribleJudgeOfCharacter genuinely believed to be a friendly, bright guy]] who he wanted to inherit RECT Inc., was in fact a major BitchInSheepsClothing who not only conducted inhumane experiments on 300 [=SAO=] survivors, but also molested Asuna and [[AttemptedRape tried to rape her]] right in front of her actual LoveInterest Kirito; not only that, but when Sugou's crimes are made public, it causes a ''massive'' public scandal that not only causes the RECT Progress branch to collapse from lawsuits, but also impacts the main company itself. Asuna's father was so horrified at how badly he misjudged Sugou that he stepped down from his position as CEO of RECT, and Asuna herself just barely managed to convince him not to retire completely.

* ''LightNovel/TrappedInADatingSimTheWorldOfOtomeGamesIsToughForMobs'':

* ''LightNovel/RebuildWorld'':
** This is Akira’s reaction to having saved Elena and Sara in what was an act motivated by hatred for their attackers rather than altruism, feeling guilty and that he must help them for genuine reasons in the future after seeing how grateful and kind they are to him over it.

** When Elena and Sara take Katsuya’s side in an argument over a major BerserkButton of Akiras, the two see the dark side of Akira’s SugarAndIcePersonality and paranoia for the first time. The two realize they DidntThinkThisThrough by judging based on only Katsuya’s perspective, and spend a long time [[MustMakeAmends trying to rebuild their friendship with Akira]].
** When Akira feels that VengeanceFeelsEmpty after [[spoiler:killing the little girl who pickpocketed him,]] he figures he MustMakeAmends by [[spoiler:sparing and saving her best friend Nasha,]] as well as confiding all of his feelings to them.

* ''Manga/KomiCantCommunicate'': Upon learning that Manbagi also has feelings for Tadano, [[spoiler: Takarazuka ends up tearfully apologizing to her for interfering and trying to use the play as a vehicle to hook Tadano up with Komi.]]

** A comedic example in the Zou arc, Usopp upgrades Nami's Clima-Tact, but Nami gets a little carried away with it, invoking this from Usopp.
--> '''Nami:''' It's easy to hold and even easier to twirl! You're the best, Usopp! ''(Unleashes lightning bolts at nearby Minks)''
--> '''Nearby Minks:''' WAAH! WATCH IT!
--> '''Usopp:''' What have I unleashed?

* Kan'u Unchou in ''Manga/IkkiTousen Great Guardians'' after realizing that for a short time she was [[{{Flanderization}} flanderized]] into a PsychoLesbian towards her liege Ryuubi. Then, she tried to kill herself as an atonement, which prompts Ryuubi to [[ArmorPiercingSlap slap her silly]] and tells her to [[GetAHoldOfYourselfMan get a hold of herself]].

** In "Attack of the Prehistoric Pokemon", Pikachu looks horrified at its reckless Thunderbolt trying to put out the dynamite Team Rocket set (which blows it up early with itself and Ash in the immediate vicinity).
** A Dragonite has this reaction in "Great Bowls of Fire" when it sees the damage its own berserk Outrage did to its forest home. Thankfully, the much smaller Pokemon who also lived there are okay and console it.

-->'''Dr. Fuji:''' "We dreamed of creating the world's strongest Pokemon... ''[[GoneHorriblyRight and we succeeded]]''..."