* Sheen in ''WesternAnimation/TheAdventuresOfJimmyNeutronBoyGenius'' episode "Sheen's Brain" after [[spoiler:he nearly kills Jimmy and Carl.]]
** Another example (although not word-for-word) is when Jimmy himself (accidentally) becomes a hall monitor in "Hall Monster". He goes... [[UnderStatement a little too far]]. Like, locking people in detention IN CAGES "too far".
-->'''Jimmy:''' [[HeelRealization Is that... me?]]
* Zummi says this in the GrandFinale of ''WesternAnimation/AdventuresOfTheGummiBears'', after his carelessness results in [[BigBad Duke Igthorn]] capturing most of the Gummis, learning the secret of [[SuperSerum Gummiberry Juice]], and taking over Dunwhyn Castle.
* Played without dialogue in ''WesternAnimation/AmericanDragonJakeLong''. In the episode "Professor Rotwood's Thesis", just the looks on Trixie and Spud's faces say it all after they discover that Jake and the dragon they just sold to Rotwood for a cash reward are one and the same.
* In an episode of ''WesternAnimation/TheAngryBeavers'', Norbert delivers this line in a neutral, almost bored, tone.
** Daggett does a comical one in "Zooing Time" when he committed a crime and got Norbert sent to the zoo for it.
-->'''Daggett''': Oh, no. What have I done accidentally on purpose?
* A comedic version happens in ''WesternAnimation/{{Animaniacs}}'' short "Temporary Insanity", twice to Mr. Plotz. The first time is when he realizes that instead of calling a temp agency, he's called the Warners and told them he needs help in the office while his secretary is out sick. The second time is when he ''agrees' to the Warners helping him out. [[HilarityEnsues Needless to say, his fears do not go unwarranted.]]
* Subverted in the pilot episode of ''WesternAnimation/AquaTeenHungerForce''. After the Rabbot that he personally built escapes and goes on a rampage, Dr. Weird dramatically exclaims "What has science done?!" Also played straight by Frylock in the episode "Super Birthday Snake". (And yes, [[MemeticMutation this is the source of the Internet-popular quote, "What Has Science Done?!"]])
* ''WesternAnimation/AvatarTheLastAirbender''
** Zuko had an extended one for the first half of the third season. His hasty actions at Ba Sing Se started to seem less heroic and more despicable, culminating in his [[HeelFaceTurn defection from the Fire Nation]] and [[CallingTheOldManOut goodbye speech]] to Ozai during the invasion. Even right after making the decision in the second season finale, he seemed almost in shock that he had betrayed his own [[ParentalSubstitute uncle]].
** Sokka doesn't say this out loud, but after seeing him relive the memory of his dad leaving after he kicks Aang out of the group for [[spoiler:hiding his father's map]], his face tells he's thinking of something like that.
** Right after yelling at Aang in the episode ''The Waterbending Scroll'', Katara immediately feels ashamed for doing so. The look Sokka gives her plainly says "[[WhatTheHellHero What the heck is wrong with you]]?!"
** Aang's reaction to burning Katara in ''The Deserter''. It was so bad that, until season 3, he swore he'd ''never'' use Firebending again.
** This was [[spoiler:Sozin's reaction to starting the war during the twilight of his life. He asks himself WasItReallyWorthIt, and concludes that no, it wasn't.]]
** Played for laughs in SequelSeries ''WesternAnimation/TheLegendOfKorra'', when Tenzin helps his son Meelo train his lemur Pokey...only for Meelo to have soon trained LOTS of lemurs! Tenzin merely mutters "I've created a monster".
** Suyin's reaction when her attempt to avoid arrest ends up scarring her sister Lin, which led to Lin hating her guts for years when mama Toph chose to protect Suyin instead of punishing her, which only hurt Lin more and further damaged their relationships with one another.
** [[AntiVillain Zaheer's]] reaction when [[spoiler:Korra reveals how his assassination of the Earth Queen allowed despotic dictator Kuvira to rise to power, he is subtly but still visibly disturbed.]]
* Dark Heart says this in ''[[WesternAnimation/CareBearsMovieIIANewGeneration Care Bears Movie II: A New Generation]]'' after discovering that, in a fit of blind rage, he's mortally wounded his only friend, Christy. [[spoiler:Saving her leads to LoveRedeems for him.]]
-->'''Dark Heart:''' '''What'''...''have I...'' done?
* In an episode of the ''WesternAnimation/CliffordTheBigRedDog'' cartoon, T-Bone has been trying to learn to be tough since he's gotten tired of everyone cooing about how cute he is. He eventually succeeds and goes about growling at anything that gets in his way. When he gets back to his house, his owner has a lady friend over and T-Bone is eager to show off how tough he is. But when he does...
-->'''Woman''': ''(climbing onto her chair and obviously frightened)'' Sheriff, there's a mean dog out here!\\
'''T-Bone''' ''(horrified)'' Mean? I didn't want her to think I was mean; just tough!
* ''WesternAnimation/CodeLyoko'':
** This happens to Jérémie Belpois in the episode "Zero Gravity Zone". He harshly berates teammate Ulrich for declining to be part of the episode's Lyoko mission in favor of going to his soccer game, assuming that [[JerkJock Ulrich is only interested in being a glory hog.]] It's not until Ulrich's left that Jérémie finds out Ulrich just wanted to impress [[AbusiveParents his dad]] since his father isn't pleased with Ulrich's [[BookDumb poor grades]]; Jérémie is appropriately upset with himself (albeit in a subdued fashion) and is quick to apologize to Ulrich at the first opportunity.
** Jim has one in "Code Earth" when, after chasing Jeremie down a flight of stairs, the genius falls down the stairs and hurts his ankle, later leading him to get fired.
*** Jeremie gets one, but it is PlayedForLaughs, as he places the wrong CD into his mainframe and it plays one of Odd's music videos instead.
** In season 4, Yumi gets angry at Hiroki for her diary being lost, and yells at him, saying she'll "never forgive him". [[spoiler: Later, however, when she's separated from the others in the Digital Sea, and it's very possible she won't survive, she regrets it, and realizes if she dies here those terrible words will be his last memory of her. Fortunately, she's rescued by the rest of the team at the last minute.]]
* On ''WesternAnimation/TheCritic'', Eleanor Sherman utters this when she finally sees firsthand the humiliating effect her book, ''The Fat Little Pig'', has on Jay's life.
* Franchise/{{DCAU}}:
** An episode of ''WesternAnimation/BatmanTheAnimatedSeries'' features a robot clone of Batman that seeks to kill Batman and take his place. Once he (apparently) succeeds at this, he goes through an existential crisis since the real Batman [[ThouShaltNotKill wouldn't kill anyone.]] He cries out "What have I done? I've taken a life!" and proceeds to smash the console evil supercomputer HARDAC was attempting to use in its evil ploy, both stopping the program and electrocuting himself, prompting the real Batman (who was hiding on a conveniently placed cliff crag) to wonder if his robot duplicate actually had a soul.
** In ''[[WesternAnimation/JusticeLeague Justice League Unlimited]]'', when [[spoiler:the League's KillSat not-all-so-accidentally fires upon Cadmus HQ]], Franchise/{{Superman}} rounds up the founding members and questions: "What have we done?" Doubly subverted, though: First, they tell him that they haven't done anything, since someone else hijacked their main computer. However, he replies that it was their choice to keep the orbital cannon, therefore all of them must take the responsibility.
** Done earlier in ''WesternAnimation/JusticeLeague'' in the episode "Hereafter" when Superman was shot into the future. He finds the last human alive, [[LivingForeverIsAwesome Vandal Savage]], who recounts how he destroyed the entire solar system in his quest for power. When he prepares to send Superman back to his time to stop him, they have the following exchange.
--->'''Superman''': What happens to you?\\
'''Savage''': Redemption, if I'm lucky.
** "[[Recap/JusticeLeagueS2E5And6OnlyADream Only a Dream]]". Stuck in a nightmare by [[DreamWeaver Dr. Destiny]], Superman thinks he's destroyed Metropolis and killed ComicBook/LoisLane, Perry White, and ComicBook/JimmyOlsen with his [[PowerIncontinence out-of-control]] superpowers. Superman doesn't actually say the words, but his tone, expressions, and body language show his devastation over what he thinks he's done.
* In the ''WesternAnimation/DefendersOfTheEarth'' episode "The Deadliest Battle", Rick starts dabbling with drugs in an attempt to relieve the pressure of having to live up to Flash's reputation. However, all the drugs do is totally mess him up, leading to, among other things, his failure to finish installing a new early warning system in Monitor. When Kshin is nearly killed (by a supercharged Ming) as a result of Rick's negligence, Rick finally realizes that DrugsAreBad.
* ''WesternAnimation/DextersLaboratory'':
** In "Way Of The Dee Dee", Dee Dee tries to make Dexter behave more like her, but she realises she's gone too far when he gets into it and begins smashing up his laboratory; she begs him to stop (which he does), wails "WHAT HAVE I DONE?!" and runs off sobbing. Dexter solemnly begins to repair the damage... and [[DownerEnding the cartoon ends.]]
** In another episode, Dexter tells Deedee he wishes her "imaginary friend" would go away so she sarcastically asks him "Why don't you just imagine him away?". Drama ensues.
-->'''Dexter:''' Koosalagoopagoop! I imagine you... away!\\
'''Koosalagoopagoop:''' Goodbye, Deedee. You'll never see me again.\\
'''Deedee:''' Dexter...\\
'''Dexter:''' What have I done?
* ''WesternAnimation/DragonBooster'': While it did not happen in the show due to cancellation, fans on the official forum all agreed that they explicitly ''did not'' want Moordryd's obviously-going-to-happen HeelFaceTurn to include a situation where he said "What have I done" in any way shape or form. Since the series was ScrewedByTheNetwork, we'll never know, but he seemed to be shaping up to be able to do without it.
* In the first season finale of ''WesternAnimation/DragonsRidersOfBerk'', Mildew has one when Alvin decides that he's [[YouHaveOutlivedYourUsefulness outlived his usefulness]], throws him in prison with Hiccup, and prepares to serve him his pet sheep as his last meal. [[spoiler:Turns out to be a subversion as it was part of a XanatosGambit so Mildew could learn Hiccup's knowledge on dragon taming to teach Alvin and his men.]]
* In the ''WesternAnimation/DuckTales1987'' episode "[[Recap/DuckTalesS1E26TheGoldenFleecing The Golden Fleecing]]", Scrooge obsessively ignores all his nephews' protests about his behavior as he tries to get the titular treasure, but when he's confronted up close and personal with the fact that his lust for the Golden Fleece [[FriendOrIdolDecision will cost Launchpad his life]], he is horrified and immediately repents.
-->'''Launchpad''': Mr. [=McDee=], help, please!\\
'''Scrooge''': What have I done? Nobody's life is worth this! I let my greed [[{{Pun}} pull the wool over my eyes]].
* ''WesternAnimation/EdEddNEddy'': Edd says "Oh dear, what have I done?!" in "Pain in the Ed" after [[spoiler: accidentally destroying Ed's violin while trying to save it from Eddy.]] It even sends him into a tear-filled HeroicBSOD.
** And in TheMovie while [[TearJerker writing a farewell letter to his parents]] [[NoodleIncident for the Eds scam]] GoneHorriblyWrong.
* ''WesternAnimation/FamilyGuy'' takes a peg from ''Series/ArrestedDevelopment'', after Stewie sends away a babysitter who possibly could've been his soulmate.
** Played for laughs in "The Kiss Seen Around the World" where Chris says this almost word-for-word after saying "poo".
* Bloo of ''WesternAnimation/FostersHomeForImaginaryFriends'' has one when his actions inadvertently cause Terrence's imaginary friend Red to have an emotional breakdown.
** Bloo has another one when he realizes how horrible he was treating Coco when she starting laying collectible baseball cards.
--->'''Bloo''': Big, Insensitive, Jerkface?!
* ''WesternAnimation/{{Futurama}}'':
** Parodied in one of the "Anthology of Interest" episodes, wherein Leela kills the professor by pushing him into a pit of man-eating anteaters:
-->'''Professor''': Ohhh, you've killed me! You've killed me!\\
'''Leela''': Oh God, what have I done?\\
'''Professor''': I just told you; you've killed me!
** Also played straight after framing Fry in destroying a bottle-ship in the episode "30% Iron Chef":
--->*Sad violin solo* '''Zoidberg''': What have I DOOONE!!!
*** Although a few laughs are mined out of it; the punishment Fry has received for said destruction is negligible and Fry doesn't seem incredibly bothered by it, but Zoidberg reacts as Fry is being sent down for murder,
** And when Leela has to hunt penguins due to severe overpopulation. After firing into a crowd of penguins, she freaks out. [[spoiler:[[RoboticReveal But it turns out she only shot]] [[GoingNative Bender]].]]
** TheMovie / MiniSeries "Bender's Big Score", when Bender [[spoiler:kills Fry under the control of an [[TheVirus evil computer virus]]]]. It screws him up that he manages to regret it rather [[RidiculouslyHumanRobots emotionally]] despite [[spoiler:the virus's effects.]]
--->[[EvilLaugh "Bwahahaha! Hahahaha...haha...]] Oh, God! ''What have I done?!?''"
** Happens again in the third installment "Bender's Game", where Leela [[spoiler:[[NotQuiteDead sort]] [[AllJustADream of]]]] kills an EldritchAbomination incarnation of Zoidberg under the belief he is an evil monster, only to learn he is not and swears off violence for a portion of the film.
** Played with again in "Jurassic Bark", after Bender throws the fossilized dog into a lava pit:
-->'''Bender''': Oh, what have I done?\\
'''Zoidberg''': You didn't do anything, don't beat yourself up.
** Yet again, in "Law and Oracle", when Fry discovers he will shoot Bender in the future, parodying ''Film/MinorityReport'':
-->'''Fry''': [[TimeTravelTenseTrouble No, no! What have I will have done?]]
* ''WesternAnimation/GalactikFootball'': Rocket says this almost word for word in the season 2 episode "The Fallen Star", after realising his Netherball opponent is actually Tia. (He thought he was playing against various previous opponents)
* Subverted by [[WoobieDestroyerOfWorlds Demona]] in ''WesternAnimation/{{Gargoyles}}'' when she sees her clan has been destroyed (and later given an IronicEcho by John Canmore):
-->"What have I...[[NeverMyFault what have THEY]] [[IgnoredEpiphany done to you]]?!"
** Inability to admit her responsibility for anything that's happened to her is Demona's defining trait, and the only way she can deal with the endless guilt. The same thing is later said by [[NotSoDifferent John Canmore]], one of the siblings from a long line of gargoyle hunters, which Demona also happened to be the source of, making it pretty ironic.
*** WordOfGod is that eventually she ''will'' have that epiphany that all of her misery and suffering is ultimately her own doing, and when that happens she'll have some change of heart and go a little mad. Considering all the times she ''almost'' realizes it and shoves it away, that epiphany is going to be difficult to cause, but she ''is'' immortal.
** Talon gets this after becoming an UnwittingPawn to Xanatos.
** Xanatos himself has such a moment when he realizes in horror what he unleashed in creating [[SdrawkcabName Thailog]] from his Machiavellian smarts and Goliath's brawn.
** And in the pilot, the wizard who originally cursed the Gargoyles to stone sleep when he thought that the princess was killed, but soon realizes his mistake after she turns up alive. Worse, because the page that contained the spell to undo the curse was burnt up.
* ''WesternAnimation/GravityFalls'':
** In "Scary-oke", Dipper has one when he unleashed a zombie horde.
** In "Society of the Blind Eye": [[spoiler: It was revealed that [=McGucket=] worked with the author of the Journals on a project that was supposed to help the world. The disaster produced this reaction from [=McGucket=], enough to drive him to erase his memories to the point of insanity.]]
** "A Tale of Two Stans" gives us a twofer; [[spoiler: in the flashback, Stan and Ford get into a fight, and during the tussle the Universe Portal activates. Ford gets this when he pushes Stan onto the heated control console, burning him horribly, and Stan does it when his counter knocks into the Portal and out of reality.]]
-->[[spoiler: '''Ford:''' ''STANLEY!'' Oh my gosh, I'm so sorry! Are you all right?!]]\\
[[spoiler: '''Stan:''' Stanford? Stanford, come back! I didn't mean it! ''(Begins fiddling with Portal controls)'' I just got him back, I can't lose him ''again! STANFORD!!'']]
* Appears to be this in the episode "A Dumb Wish" in ''WesternAnimation/TheGrimAdventuresOfBillyAndMandy'' with Mandy when she [[BeCarefulWhatYouWishFor accidentally wishes everyone on Earth away into oblivion]] ...but then she gives an devilish smirk and goes home to watch TV.
** Then played straight in the episode "Billy and Mandy vs. The Martians". Grim has this moment after he [[FaceHeelTurn willingly helped the Martian Grim Reaper, Morg, invade Earth and turn everyone into zombies]], and used Billy as a way to control said zombies. He begins to have his HeelFaceTurn after discovering that [[spoiler: Morg had destroyed the Reapers of all the other planets and kept their scythes as trophies, and that he might [[YouHaveOutlivedYourUsefulness possibly do the same to Grim after he successfully conquered the universe]].]] And surprisingly, it's ''Billy'' of all people that finally talks Grim back to his senses.
--->'''Billy:''' Sometimes our best friends are people we really don't like.\\
'''Grim:''' Then you guys must be my best friends ever.\\
'''Billy:''' Well, if there's anything I've learned from [[ItMakesSenseInContext destroying Fancy Jake]] and stowing away in your trunk to Mars, and returning in a last-ditch effort to save the planet, is that you can pick your friends, and you can pick your nose, but you can't pick your friend's nose. You have to let them be who they are, and pick it themselves.\\
'''Grim:''' ...''What have I done?!''
* In the ''WesternAnimation/HeManAndTheMastersOfTheUniverse1983'' episode "The Problem With Power", Skeletor tricks He-Man into believing he's killed an innocent bystander (really a minion who was FakingTheDead) with his carelessness. In the HeroicBSOD that follows, He-Man retires. Fortunately, Orko finds out about the trick, and tells He-Man.
* ''WesternAnimation/HeyArnold'':
** During a Halloween Episode, the kids go trick-or-treating disguised as aliens. Unfortunately, a Radio/TheWarOfTheWorlds-style radio broadcast convinces the adults that it's an actual alien invasion, who then form a lynch mob out to get the kids. (It doesn't help that they accidentally used exterior latex paint instead of facepaint, which doesn't rub off.) At the climax, Bob Pataki grabs Helga by the neck and starts choking her, only to realize his mistake when it starts raining and the paint finally washes away.
--> "I almost killed my own daughter. I'm a monster!"
** Arnold felt this when he blinds Helga on April Fool's Day.
** In the universally-despised episode "Arnold Betrays Iggy", Arnold accidentally discovers that Iggy wears bunny pajamas, and Sid and Stinky find out and quickly blab it to everyone; Iggy, believing that Arnold did so, is so pissed that he repeatedly blows off all of Arnold's attempts to earn his forgiveness, ultimately deciding that the only way Arnold could possibly do so is by putting on the bunny pajamas himself and grovelling at Iggy's feet in full view of the entire neighborhood. It's only when Arnold does so, and is subsequently humiliated in public, that Iggy overhears that Sid and Stinky merely figured it out on their own and realizes his mistake. Unfortunately, when he arrives to apologize to Arnold the next day, Arnold angrily blows him off; in the end, even though Iggy regretted his actions, it was [[MoralEventHorizon too late for him to fix anything]].
* Jackie Chan from ''WesternAnimation/JackieChanAdventures'' yells this in the second episode of season 3 when he realizes that destroying the talismans which results in its powers to be transferred to the animals is not really a good idea.
* When Captain Hook gained the power to turn stuff into gold in ''WesternAnimation/JakeAndTheNeverlandPirates'', he went crazy and accidentally turned two of his crew mates into gold. He uttered those words. And ended up just running around turning Neverland into gold.
* ''WesternAnimation/{{Kaeloo}}'': Kaeloo's reaction to seeing her friends (usually [[VillainProtagonist Mr. Cat]]) severely beaten up by her after [[JekyllAndHyde transforming]].
** Kaeloo, Mr. Cat and Quack Quack's reaction in Episode 105 to [[spoiler: realizing how horribly they've treated Stumpy until then]].
** In Episode 125, [[spoiler: Mr. Cat shoots [[NighInvulnerable Quack Quack the indestructible duck]] with a bazooka, but he soon finds out that Quack Quack isn't getting up and is actually dead. Upon realizing what he's done, [[OOCIsSeriousBusiness Mr. Cat starts crying. The scene cuts to him at Quack Quack's funeral looking especially sad]]. However, he doesn't do anything to indicate that he's happy when Quack Quack comes BackFromTheDead.]]
* In an episode of the ''ComicStrip/KrazyKat'' animated series, Krazy is BornLucky, and Ignatz is jealous and wants her luck for himself. Then he comes up with the perfect solution -- he'll give her some CementShoes, get her to sign her luck away to him, then dump her underwater. Only after he's already done this does he have this reaction and dive underwater to save her.
--> "I must have been insane!"
* In episode 2 of ''WesternAnimation/TheLegendOfPrinceValiant'', Valiant stumbles into the territory of a large man who angrily orders him to get out and attacks him. Valiant defends himself, but loses his temper and nearly beats the man to death. While Arn says he was justified, Valiant is horrified and atones by treating the man's injuries and taking him to his mother.
* ''WesternAnimation/LooneyTunes'':
** One of the best known examples is in the short, "WesternAnimation/WhatsOperaDoc" where Elmer Fudd, after spending the whole short exulting in [[Music/RichardWagner Wagnerian]] time that he would "Kill the Wabbit!", laments what he's done after he does it. (He also does this in some other shorts, but this was the most recognizable instance.)
** This goes back to the very first Bugs short, "WesternAnimation/AWildHare", in which he shoots at Bugs and then Bugs plays dead, causing Elmer to break down in tears and call himself a murderer.
** Which asks the question of [[FridgeLogic why does Elmer even go hunting?]]
*** It could be that Bugs' "death" scene is played out with so much gusto and pathos that Elmer is left feeling ultimately guilty. Or possibly that Elmer's used to Cartoon Logic by this point (i.e, Daffy Duck being only humiliated when shot).
** Spoofed in "The Wabbit That Came to Supper"; Elmer is willed $3 Million, OnOneCondition; that he not harm a living creature- especially rabbits. Bugs proceeds to be TheThingThatWouldNotLeave, until Elmer tricks him into going out the door. Bugs feigns death from the cold, leading Elmer to lament that he's indirectly killed his nemesis; "Ohh, what have I done!? Three miwwion bucks! Shot to pieces!"
** The dog in "Hare Ribbin'" does this after he takes a bite of the rigged "rabbit sandwich" Bugs makes for him and Bugs plays out his "death" scene.
** Bugs himself zig-zags this in "Falling Hare" as he almost takes the Gremlin's mallet to a blockbuster bomb.
--->'''Bugs:''' [[NoIndoorVoice WHAT]] [[OhCrap AM I DOING???!!]]
* In the episode "Fatherklok" of ''WesternAnimation/{{Metalocalypse}}'', Skwisgaar says this after pushing his stepfather in a fit of rage and causing him to hit a coffee table - it breaks underneath him, and he groans in agony as he looks at the shards of glass embedded in his hand.
* In ''WesternAnimation/MarvelsSpiderMan'', Peter cries out in anguish "WHAT HAVE I DONE?!" when he catches the criminal who killed his Uncle Ben and realizes it's the crook he let get away earlier.
* In the segment opening of the cartoon of ''The WesternAnimation/MiltonTheMonster Show'', Professor Weirdo says this when Milton -- made kind and lovable after having too much kindness added to him -- arises.
* At the beginning of the ''WesternAnimation/MoonbeamCity'' episode "Lasers and Liars", [[CluelessDetective Detective]] [[CowboyCop Dazzle]] [[TheHero Novak]] snarks about [[DaChief Chief]] Pizzaz [[FallenPrincess Miller]]'s menstrual cycle and [[AllPeriodsArePMS accompanying mood swings]], and cluelessly muses about [[spoiler:his and Pizzaz's annual romantic/intimate tryst]] during the previous year's weekend-long "Cop Con". He then accidentally hints that [[spoiler: [[MySecretPregnancy the two conceived a child]]]], but that Pizzaz [[spoiler: [[ConvenientMiscarriage lost the baby]] during the first trimester]]. Pizzaz is so enraged at Dazzle for letting this info slip that she [[BigShutUp viciously slaps him silent]], shrieking "THAT'S ENOUGH!" and leaving a visible hand print across his face. Yet for all the threats she usually makes to Dazzle, Pizzaz becomes immediately and incredibly horrified at the fact that she just physically assaulted Dazzle, remembering that angry slapping is [[spoiler:the preferred form of interpersonal violence for Pizzaz's four malicious, sadistic, and abusive older sisters]].
* ''WesternAnimation/MyLittlePonyFriendshipIsMagic'':
** In the episode "Lesson Zero", Twilight Sparkle has this reaction after her insane attempt to create a friendship problem via an AppleOfDiscord [[GoneHorriblyRight goes horribly, horribly, right.]]
** In "Sisterhooves Social", Rarity totally loses it with her sister after an entire day of getting on one another's nerves (including when Sweetie Belle makes a picture out of the rare gems Rarity had been saving for a dress for an important client), resulting in a huge argument which makes both swear that they wished they were only children and storming off. Later on she's tidying up and looks at the picture again, [[spoiler:shown for the first time to be a picture of the two nuzzling inside a shining blue heart.]] Rarity’s reaction is almost word for word.
** She ''sings'' "what have I done" in "Rarity Takes Manehattan," when her friends don't show up for her fashion show and she thinks she has alienated them. [[spoiler:They actually just overslept because they were exhausted from helping her sew new dresses the night before.]]
** "Secret of My Excess": Spike doesn't come right out and say it, but the emotion is conveyed by his reaction to seeing Ponyville devastated, and his own giant footprints.
** Happens in "Hearth's Warming Eve" when Clover the Clever (Twilight), Smart Cookie (Applejack), and Private Pansy (Fluttershy) discover that the blizzard that destroyed their homeland and is now threatening Equestria is caused by Windigos, winter spirits that have been [[EmotionEater feeding off of]] [[ThePowerOfHate the hatred between the three tribes of ponies]], meaning their pointless hatred for one another was the cause of everything that has happened.
** In "Baby Cakes", despite being only a month old, the Cake Twins are smart enough to realize they've [[BadlyBatteredBabysitter gone too far]] when they see Pinkie [[OcularGushers bawling]].
** ''The entire town of Ponyville'' gets one in "The Super Speedy Cider Squeezy 6000", when their support of the Flim Flam brothers almost causes the Apple family to ''lose their entire livelihood.''
** Fluttershy gets one in "Putting Your Hoof Down" after being a huge bitch to Pinkie Pie and Rarity, due to taking her assertiveness lessons from Iron Will.
** Twilight has one in "A Canterlot Wedding" when everyone calls her out on calling Cadance evil. [[spoiler:The twist is that it wasn't really Cadance at all, but an impostor posing as her.]] Thus, when she reveals that [[spoiler:the first Cadance she met is an impostor by helping the real Cadance escape]], everyone else has this when they realize [[spoiler:'''she was right'''. The impostor, the changeling queen Chrysalis, rubs into their faces that if they had just ''listened'' to Twilight, she could have been stopped. Applejack goes to apologize to Twilight during the NearVillainVictory, but the latter brushes it off and doesn't hold against them, stating that Chrysalis had fooled everypony and that it wasn't their fault.]]
** The Cutie Mark Crusaders, fed up with Babs Seed bullying them to impress resident bitches Diamond Tiara and Silver Spoon, [[TheDogBitesBack set her up for a humiliating fall]]. Then they learn from Applejack that [[spoiler:she's being bullied herself back in Manehattan]].
--->'''All three''': WHAT'D WE DO!?
** [[RealityWarper Discord]] of all people has one of these moments in his returning episode when he realizes that Fluttershy, [[spoiler:the only pony to have shown faith and trust in his rehabilitation]], takes his jokes and her patience too far when he floods Apple Acres.
** Twilight says "What have I done?" in "Magical Mystery Cure" [[spoiler:after discovering that her careless use of magic has ruined her friends' lives and made all of Ponyville miserable, and she doesn't know how to undo it.]].
** In ''[[Recap/MyLittlePonyFriendshipIsMagicS4E26TwilightsKingdomPart2 Twilight's Kingdom Part 2]]'', Discord is obviously having second thoughts during his team up with Tirek. But this trope doesn't hit him completely until Tirek, unsurprisingly, betrays him and takes his power, just like he did to Fluttershy.
** In "For Whom The Sweetie Belle Toils" Sweetie Belle gets a massive one, as due to a tiff, she sabotages Rarity's hat that she is to present to a celebrity that will make or break her career. Luna shows Sweetie Belle what would happen if she doesn't fix things before the presentation. Which includes, the hat being a complete joke, Rarity being the laughing stock of Equestria, losing her confidence as she couldn't figure out what she did wrong, going literally insane and isolating herself from all of her friends to the point of being a crazy cat lady.
** [[spoiler: Starlight Glimmer]] gets this reaction in ''The Cutie Re-Mark Part 2'', [[spoiler: When she learns the hard way what her diabolical plan to change history will eventually lead to. Equestria becomes ''[[BadFuture a completely barren wasteland]]'', and hardly the grand utopia of equality she imagined]].
* [[EvilCounterpart Sunset Shimmer]] has one in ''WesternAnimation/MyLittlePonyEquestriaGirls'' after [[OneWingedAngel transforming into a "raging she demon"]], turning a high school into her own personal army, and nearly killing Twilight Sparkle, triggering her HeelFaceTurn.
* While not uttered, Rabbit from ''WesternAnimation/TheNewAdventuresOfWinnieThePooh'' has one of these moments after realizing Pooh was trying to help him in fetching honey (Before this, he had tricked Pooh into thinking he's moving away due to Pooh's constant borrowing for honey.) what follows is one of the show's [[Heartwarming/TheNewAdventuresOfWinnieThePooh more heartwarming moments]].
* In the ''WesternAnimation/PhineasAndFerb'' episode "[[SpoilerTitle Phineas and Ferb Get Busted]]", Candace cries this out through TearsOfRemorse when her brothers have had their personalities wiped clean due to her actions. Luckily, the episode is AllJustADream.
* ''WesternAnimation/PinkyAndTheBrain'':
** The Brain starts to realize that he has a problem when he goes a little crazy and accidentally pushes Pinky off of the table (or whatever it is that they're on):
--->'''Brain''': What have I done? Pinky! Are you all right?\\
'''Pinky''': Uh huh. Narf! But I'm afraid my secret playhouse will never be the same... (''he had landed on top of it'')\\
'''Brain''': Oh, it's all my fault. This obsession with taking over the world is causing me to hurt the ones I... [[LastSecondWordSwap tolerate]].
*** This event prompts Brain to go to an organization called Megalomaniacs Anonymous in an attempt to get over his obsession with world domination. In a subversion, he decides in the end to return to his quest, since it's actually "a mission of mercy" -- if he ruled the world, it would be a better place for everyone. (This ties in with a subdued, implied MindScrew of the series: the title song only promised that "one is a genius, the other insane" but never stated which was which.)
** Played for laughs when Brain concocts a scheme to use a time machine to alter the past in order to make mice the dominant species, therefore making it easy for him to take over the world. He succeeds, but unfortunately, all the mice citizens are basically Pinky clones, horrifying Brain. He quickly tries to reset everything back to the way it was as he didn't even want to think about ruling a world of idiots.
--->'''Pinky''': But why, Brain? With things like this, it should be easy for you to take over the world.\\
'''Brain''': That may be true, Pinky, but who would want to!?"
** Played without dialogue in the ChristmasSpecial, after Brain ignores Pinky sobbing over his "stupid letter" to Santa he never got round to delivering, and eventually confiscates it in anger. Just before his plan is set in motion, he reads it out of curiosity, to find it is in fact a heartwrenching speech about his "best friend in the whole world, the Brain" and pleading for Santa to give every present intended for Pinky to him instead, since he never gets any reward for his hard effort. By the end of the letter, Brain is left in blubbering tears from remorse and aborts the scheme.
* In one episode of the 2010 ''[[WesternAnimation/PoundPuppies2010 Pound Puppies]]'', Niblet says it when he sees that his angry outburst at his [[GenkiGirl hyperactive little sister]] caused her to hitch a ride with [=McLeish=]'s dog-hating mother.
* ''WesternAnimation/ThePowerpuffGirls'':
** The girls have this moment at the end of "Twisted Sister". [[spoiler: Bunny dies after she saves the girls. Earlier in the episode, the girls had been mean to her, treating her like a mistake - which was, in itself their fault. Even the narrator is saddened.]]
** The girls again have this moment in "Candy is Dandy" after they give Mojo Jojo a severe NoHoldsBarredBeatdown after he hords the Mayor's candy jar from them.
** The Professor has this moment in "Criss Cross Crisis" after his latest experiment causes everyone in Townsville to switch bodies.
* Captain Capacitor from ''WesternAnimation/ReBoot'' says this in a direct reference to ''Film/StarTrekIIITheSearchForSpock'' while watching [[spoiler:his ship, the ''Saucy Mare'', get shot out of the sky onto enemy forces while packed with explosives]].
* ''WesternAnimation/{{Rugrats}}'' plays with this. Chuckie says this when he's told to release a balloon holding Angelica's doll. Susie said it was Angelica who released it as punishment. Phil and Lil, well...
-->'''Phil:''' I thought Chuckie let go of the balloon.\\
'''Lil:''' No, Angelica let go of the balloon. You just weren't paying attention.\\
'''Phil:''' Oh.
** A few straighter examples happen towards Angelica, though [[AesopAmnesia they usually don't stick]]. One episode had Angelica running away to get back at her being punished only to find Drew at Tommy's house laughing and having a good time (she thought he was ''happy'' she was gone; he hadn't realized Angelica ''left'') but it still hurt her enough to realize she made a mistake. Another time had Angelica covering herself with "vanishing cream" to make herself "invisible" at the same time Didi got Drew to enforce ignoring her to get her to stop. Again, major coincidences got Angelica to realize how horrible she'd been.
*** Angelica gets a ''big'' moment of this in ''WesternAnimation/RugratsInParis'' when Coco heads off to marry Chaz, ordering Chuckie's [[TragicKeepsake beloved bear Wawa]] [[KickTheDog destroyed]] and Chuckie breaks down; it drives her to ''apologize'' for what she did.
* ''WesternAnimation/TheSimpsons''
** Parodied in the episode "Simpsons Tall Tales". In a retelling of the Johnny Appleseed story, Homer realizes he singlehandedly hunted the buffalo (their main food source) to extinction:
-->'''Homer''': What have I done? What have I done???\\
'''Bart''': Dad! Look! There's still two left!\\
''[WhipPan over to two buffaloes who are promptly shot dead]''\\
'''Homer''': (holding a still smoking shotgun): What have I done? What have I done???
** Also parodied in "Homer's Odyssey", when he steals and breaks open Bart's piggy bank for beer money:
-->'''Homer''': Oh no! What have I done? I smashed open my little boy's piggy bank, and for what? A few measly cents, not even enough to buy one beer. Wait a minute, lemme count and make sure... not even close.
** Parodied ''again''.
-->'''Homer:''' What have I done?! What am I doing?! What will I do?!
** Also in the episode "24 Minutes" [[spoiler:Martin betrays the good guys by handing Bart over to the bullies in exchange for his Ant Farm. After realizing what he did and the consequences of it, he says "What have I done?!" out loud. Martin goes to a nearby room by himself as dark, sad music plays. We then see him hanging himself... until the camera pans out revealing he's hanging from his underpants, thus giving himself a wedgie]]
** In "Bart The Lover" Bart answers Mrs. Krabapple's personal ad by pretending to be the world's perfect lover, ultimately setting her up for a PrankDate. This is his reaction when he sees just how hurt his teacher is.
** Played straight in "When Flanders Failed". Homer, jealous of Flanders' success, wishes that Ned's ''Leftorium'' falls apart. When he sees Flanders' business doing poorly, and doesn't bother to tell his left-handed friends about the products they need, [[KickTheDog and to twist the knife]], smugly buys Flanders' stuff for cheap. He reacts this way to seeing Flanders family forced to live in their car.
* ''WesternAnimation/SouthPark'':
** In "Something Wall-Mart This Way Comes," one of the creators of Wall-Mart exclaims, "Jesus, what did we do?!" [[spoiler:and then [[DrivenToSuicide shoots himself]]. And then [[NoDeadBodyPoops craps his pants]].]]
** The mayor of South Park also utters this after surveying the Hippie Music Jam Fest that she signed the permit for in "Die, Hippie, Die."
** The sellers of Ritalin use this exact phrase (well, in plural form) when they learn that by prescribing it to everyone, they now have a town full of children who [[FelonyMisdemeanor like Phil Collins]].
** "Raising the Bar" has everyone realizing just how low they sunk in life and wondered what on earth had made them act like such lowlives once the bar was raised.
** Kyle experiences a textbook case of this in "Toilet Paper" after [[FelonyMisdemeanor TPing a teacher's house]].
** Mr. Adams reacts this way in "The Poor Kid" when he sees how awful the foster home he sent some children to is.
** Sergeant Yates leads a mission to arrest "[[Music/MichaelJackson Mr Jefferson]]" after reading on his file that he's rich and black. When his target arrives home and is revealed to be white, Yates is horrified at the injustice that he nearly committed, causing him to vomit and to consider quitting his job.
** Kyle's dad experiences one in "Chickenpox". After fighting with Kenny's dad, he explains to his son that the world runs on a hierarchy of gods and clods. Then he sees a note written by Kyle thinking that [[ThoseWackyNazis the world would be a much better place if the gods got rid of all the clods]]...
** Another one Kyle's dad experienced was in "The Damned", when he found out the Danish breast cancer survivor he's been trolling online [[spoiler: commited suicide.]] It's then [[SubvertedTrope subverted]] when it becomes clear that he doesn't give a damn about the fact his trolling caused someone so much emotional pain, he's just afraid of getting caught and into trouble because of it.
** Kyle has one after his action led to [[spoiler: Garrison to nuke Canada in a fit of anger.]] It basically makes the aforementioned TPing look like an afterthought.
* In ''WesternAnimation/SpaceGhostCoastToCoast'', one episode deals with a pledge drive that's not going very well. Frustrated, Space Ghost orders the audience to give him money, or he'll shoot Brak. Brak starts crying, and Space Ghost feels ashamed of what he's doing. Brak calms down and tells him that "it's okay", which Space Ghost cheerfully takes as permission to shoot him.
** In another episode, Space Ghost takes revenge on Zorak for thrashing his apartment by blasting him so many times he ceases to exist (or so he thinks). When he realizes that he actually killed him, Space Ghost shouts "Heaven help me, what have I done?!" before casually following up with "Oh well" and continuing the show without him.
** In a third episode, Space Ghost's pet sea monkey Banjo grows to immense size and starts blasting Zorak, causing Space Ghost to bellow "What have I unleashed?!" Then Space Ghost kills Banjo, which prompts another moment.
--->'''Space Ghost:''' Banjo. Banjo! BAN-JOOO!!!
* The 1990's ''WesternAnimation/SpiderManTheAnimatedSeries'' took a number of steps to making J. Jonah Jameson more sympathetic, but one of the more [[MythologyGag meaningful to fans of the comic]] was his pulling this when Mac Gargan, aka the man Jameson turned into the Scorpion to defeat Spider-Man, went on the rampage.
* ''WesternAnimation/SpongeBobSquarePants:''
** In "Band Geeks", after everybody that Squidward gathered for 4 nights of band practice, and on the final night, fought over differences and hurt Squidward's feelings:
--> '''[=SpongeBob=]:''' What kind of monsters are we?...
** Mr. Krabs also goes through this in the episode "Born Again Krabs" after Squidward [[WhatTheHellHero calls him out for trading [=SpongeBob=] for just sixty two cents]].
** In the episode "Have You Seen this Snail?" when [=SpongeBob=] realizes he made Gary run away from home after he neglected to feed him. Patrick lampshades this.
** In the episode "Procrastination", [=SpongeBob=] cries this when his procrastination ends up getting his house set on fire.
-->'''[=SpongeBob=]'s House:''' ''Why, [=SpongeBob=]!? Why didn't you just write your essay! STOP WASTING TIIIIIME!.''
** And in the Season 6 episode "Giant Squidward", he and Patrick actually feel ''guilty'' about turning their titular neighbor into a giant.
** In "Frankendoodle", [=SpongeBob=] and Patrick find a magic pencil that can make their drawings come to life, and [=SpongeBob=] draws a doodle of himself to prank Squidward. The doodle then proceeds to beat up Squidward, steal the magic pencil, and run away, causing [=SpongeBob=] to utter this line once he realizes what he created.
** In "Whatever Happened to [=SpongeBob=]?", all of [=SpongeBob=]'s friends (except Squidward) and pet are left in saddened regret when they find out he left because they got mad and chewed him out for the accidents he caused, not to mention called him an "idiot boy".
-->'''Mr. Krabs''': ''(after reading [=SpongeBob=]'s farewell letter)'' "IDIOT BOY"?! It ''is'' [=SpongeBob=]! What am I gonna do without me fry cook?\\
'''Patrick''': What am I gonna do without my best friend? I never should have been mean to you! ''(cries)''\\
'''Sandy''': I should have never kicked you out of my house! ''(cries, with her tears filling up her helmet)''\\
'''Squidward''': ''(near tears)'' If I knew that was the last time I've seen [=SpongeBob=]--- ''(happily)'' [[JerkWithAHeartOfJerk I would have slammed the door in his face even harder!]] ''(laughs)''
** Gary has one in "Gary's New Toy" when his obsession with his new squeaky ball toy drives [=SpongeBob=] into packing up and leaving home.
** In "Funny Pants", Squidward tricks [=SpongeBob=] into thinking he lost his laugh box. [=SpongeBob=] is eventually left crying hysterically thinking he can't laugh anymore, causing Squidward to utter this line.
** Squidward has one much earlier in "Fools in April" after making [=SpongeBob=] cry with a rather painful April Fool's prank.
* ''WesternAnimation/StarWarsTheCloneWars'': In the Umbara Arc's [[Recap/StarWarsTheCloneWarsS4E10CarnageOfKrell "Carnage of Krell"]], the clone troopers of both the 501[[superscript:st]] and the 212[[superscript:th]] show signs of this after realizing that [[spoiler:General Pong Krell had tricked them into attacking and killing each other by separately telling each battalion that the enemy was disguised as the other battalion.]] Captain Rex, who is usually cool and collected, [[HeroicBSOD visually breaks down]]. Tup puts it into words:
-->"This can't be happening. What have we done?"
* ''WesternAnimation/StevenUniverse'':
** PlayedForLaughs during "Rising Tides"/"Crashing Skies". Ronaldo realises he's convinced the thing that was [[CharacterBlog keeping Beach City weird]] to leave, at which point he howls "WHAT HAVE I DONE?" at the ceiling; of course, being [[IJustWantToBeSpecial Ronaldo]], he's [[SkewedPriorities upset that it means he won't have anything to blog about]]. InelegantBlubbering ensues.
** Also used seriously. Such as in "Cry for Help", where at the end of the episode Pearl realizes [[spoiler: that by lying to Garnet in order to create situations in which to fuse with her, Garnet is now betrayed and ''absolutely furious'']]. We have a long shot of her eyes wide open in terror as she clutches her stomach. The next episode, "Keystone Motel" also features [[spoiler: Ruby and Sapphire]] realizing that their arguing has been hurting everyone around them, especially Steven, who now blames himself.
** In "Message Received", Peridot has this reaction as she realizes that she [[spoiler:called Yellow Diamond a clod. To her face]]. Unlike most examples, this is a positive use of this trope.
** Sardonyx has a sizeable moment of this in "Know Your Fusion", after spending the episode hijacking [[spoiler:Smoky Quartz's]] big debut and comparing them to other fusions, causing [[spoiler: Smoky]] to start taking self-depreciating shots at themself as their insecurity rises to the surface. Sardonyx is so upset by her own behavior that she unfuses on the spot.
* A HUGE one happened in the episode "Before the Dawn" of ''WesternAnimation/YoungJustice'': [[spoiler:Miss Martian, who lately has been VERY trigger happy with the MindRape button, attacks Aqualad and leaves him a drooling vegetable... only during the MindRape, she glances into his memories and realizes that Aqualad never betrayed the team, but was a deep cover mole for both Young Justice and the [[JusticeLeagueOfAmerica Justice League]], and all the supposed bad stuff he did were actually diversionary tactics to earn The Light's trust. Cue HeroicBSOD.]]