- A HUGE one happened in the episode "Before The Dawn" of Young Justice: Miss Martian, who lately has been VERY trigger happy with the Mind Rape button, attacks Aqualad and leaves him a drooling vegetable... only during the Mind Rape, 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 Justice League, and all the supposed bad stuff he did were actually diversionary tactics to earn The Light's trust. Cue Heroic BSOD.
- In an episode of The Angry Beavers, Norbert delivers this line in a neutral, almost bored, tone.
- One of the best known examples is in the Looney Tunes short, "Whats Opera Doc" where Elmer Fudd, after spending the whole short exhorting in 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, " A Wild Hare", 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 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).
- 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.
- Parodied in Futurama, 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!
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 Minority Report:
- Dragon Booster: 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 Heel-Face Turn to include a situation where he said "What have I done" in any way shape or form. Since the series was Screwed by the Network, we'll never know, but he seemed to be shaping up to be able to do without it.
- In the episode "Fatherklok" of 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.
- Family Guy takes a peg from Arrested Development, 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".
- Subverted by Demona in Gargoyles when she sees her clan has been destroyed (and later given an Ironic Echo by John Canmore):
- 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 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.
- Talon gets this after becoming an Unwitting Pawn to Xanatos.
- Xanatos himself has such a moment when he realizes in horror what he unleashed in creating 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.
- Subverted in the pilot episode of Aqua Teen Hunger Force. 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, this is the source of the Internet-popular quote, "What Has Science Done?!")
- Parodied in The Simpsons 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!
[Whip Pan 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.
Homer: What have I done?! What am I doing?! What will I do?!
- Also in the episode "24 Minutes" 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
- Sheen in The Adventures of Jimmy Neutron: Boy Genius episode "Sheen's Brain" after 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... a little too far. Like, locking people in detention IN CAGES "too far".
- In one episode of Pinky and the Brain, 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.)
: Oh, it's all my fault. This obsession with taking over the world is causing me to hurt the ones I... 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 Mind Screw 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 Christmas Special, 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.
- An episode of Batman: The Animated Series 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 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 Justice League Unlimited, when the League's Kill Sat not-all-so-accidentally fires upon Cadmus HQ, 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 Justice League in the episode "Hereafter" when Superman was shot into the future. He finds the last human alive, 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.
- Appears to be this in the episode "A Dumb Wish" in The Grim Adventures of Billy & Mandy with Mandy when she accidentally wishes everyone on Earth away into oblivion ...but then she gives an devilish smirk and goes home to watch TV.
Billy: Sometimes our best friends are people we really don't like.
Grim: Then you guys must be my best friends ever.
Well, if there's anything I've learned from 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?!
- Zummi says this in the Grand Finale of Adventures of the Gummi Bears, after his carelessness results in Duke Igthorn capturing most of the Gummis, learning the secret of Gummiberry Juice, and taking over Dunwhyn Castle.
- In Space Ghost Coast to Coast, 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!!!"
- South Park:
- In "Something Wall-Mart This Way Comes," one of the creators of Wall-Mart exclaims, "Jesus, what did we do?!" and then shoots himself. And then 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 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 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.
- Edd says "Oh dear, what have I done?!" in "Pain in the Ed" after accidentally destroying Ed's violin while trying to save it from Eddy. It even sends him into a tear-filled Heroic BSOD.
- Possible villainous use in Avatar: The Last Airbender, when Ozai accidentally fixed Aang's chakra flow with an Improbability Drive rock. You know that as Aang was kicking his can all over the place, Ozai was just thinking "What the hell did I do?!"
- Aang's got your beard!
- 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 goodbye speech to Ozai during the invasion.
- 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 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 "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 Sozin's reaction to starting the war during the twilight of his life. He asks himself Was It Really Worth It?, and concludes that no, it wasn't.
- Played for laughs in Sequel Series The Legend of Korra, 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.
- Dark Heart says this in Care Bears Movie II: A New Generation after discovering that, in a fit of blind rage, he's mortally wounded his only friend, Christie. Saving her leads to Love Redeems for him.
Dark Heart: What...have I... done?
- In one episode of the 2010 Pound Puppies, Niblet says it when he sees that his angry outburst at his hyperactive little sister caused her to hitch a ride with McLeish's dog-hating mother.
- On The Critic, Eleanor Sherman utters this when she finally sees firsthand the humiliating effect her book, The Fat Little Pig, has on Jay's life.
- 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.
- A few straighter examples happen towards Angelica, though 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.
- In the Phineas and Ferb episode "Phineas and Ferb Get Busted", Candace cries this out through Tears of Remorse when her brothers have had their personalities wiped clean due to her actions.
- SpongeBob SquarePants: 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 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.
- In the episode "Procrastination", Spongebob cries this when his procrastination ends up getting his house set on fire.
Spongbob'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.
- My Little Pony: Friendship Is Magic:
- Sunset Shimmer has one in My Little Pony Equestria Girls after transforming into a "raging she demon", turning a high school into her own personal army, and nearly killing Twilight Sparkle, triggering her heel face turn
- A comedic version happens in 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. Needless to say, his fears do not go unwarranted.
- In an episode of the Krazy Kat animated series, Krazy is Born Lucky, and Ignatz is jealous and wants her luck for himself. Then he comes up with the perfect solution—he'll give her some Cement Shoes, 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 the He-Man and the Masters of the Universe (1983) episode "The Problem With Power", Skeletor tricks He-Man into believing he's killed an innocent bystander (really a minion who was Faking the Dead) with his carelessness. In the Heroic BSOD that follows, He-Man retires. Fortunately, Orko finds out about the trick, and tells He-Man.
- During a Halloween episode of Hey Arnold!, the kids go trick-or-treating disguised as aliens. Unfortunately, a The War of the Worlds-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 too late for him to fix anything.
- Madagascar. Kind of a "My God, What Did I Almost Do?" moment with Alex after he almost kills Marty, who is luckily saved by Maurice dropping a coconut on Alex's head, which then leads up to Alex saying, "Oh no. What have I done?" and then realizing he's too dangerous to be around his friends, including Marty and deciding to leave for their own safety.
- Marty says this word for word when he realizes that his bringing his friends into the wild caused Alex to almost revert to his predatory instincts and leave them.
- 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)
- In episode 2 of The Legend of Prince Valiant, 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.
- Bloo of Foster's Home for Imaginary Friends 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?!
- The 1990's Spider-Man: The Animated Series took a number of steps to making J. Jonah Jameson more sympathetic, but one of the more 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.
- In the first season finale of Dragons: Riders of Berk, Mildew has one when Alvin decides that he's outlived his usefulness, throws him in prison with Hiccup, and prepares to serve him his pet sheep as his last meal. Turns out to be a subversion as it was part of a Xanatos Gambit so Mildew could learn Hiccup's knowledge on dragon taming to teach Alvin and his men.
- Jackie Chan from Jackie Chan Adventures 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.
- Captain Capacitor from ReBoot says this in a direct reference to Star Trek III: The Search for Spock while watching his ship, the Saucy Mare, get shot out of the sky onto enemy forces while packed with explosives.
- While not uttered, Rabbit from The New Adventures of Winnie the Pooh 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 more heartwarming moments.
- In Dexter's Laboratory's "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 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.
Dexter: What have I done?
- In the DuckTales episode "The Golden Fleecing", Scrooge is horrified when he realizes that his lust for the Golden Fleece is about to get Launchpad killed.
- In the segment opening of the cartoon of The Milton The Monster Show, Professor Weirdo says this when Milton—made kind and lovable after having too much kindness added to him—arises.
- Gravity Falls: In Scary-oke, Dipper has one when he unleashed a zombie hoard.
- In Society Of The Blind Eye: 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.