In the Manga version of Sailor Moon, Queen Beryl actually has one of these, very briefly musing how she's sold her soul to Metallia and that there's no going back.
Future Diary has one, with Yuno about to kill her third self, and realizing how twisted she has become, before deciding to attempt it anyway. Then AGAIN, when she is about to kill her family, realizes how much she loves Yuki, and how amazing he is for changing the future to allow her family to come together and be happy. She then attempts to kill all three of them anyway.
Vegeta is a weird case. He was reduced to a sobbing Final Speech, disgusted by what he'd turned into and begging Goku to destroy Frieza so that it wouldn't happen to anyone else. Once revived, he's right back to being a huge Jerk Ass and threatening to take over the universe; he then remains a dormant villain for years, and while he does eventually make a Heel-Face Turn, the exact moment is hard to pinpoint and it doesn't seem to be related to the first epiphany.
Him being disgusted at himself was just Dub Text FUNI added in. In the Original version, he never says anything of the sort, but just begs for Frieza to "fall by a Saiyan's hand", as revenge for his race.
Paul from Pokémon has done this one time, when he battled Cynthia and got royally curb-stomped, she told him he needed to treat his Pokémon with love and respect, which he scoffed at.
Yu-Gi-Oh! GX: Jaden as the Supreme King believes that he killed Jim, one of his newer friends, in a heated duel. Then he casually turns to Axel and asks "So are you next?".
Yu-Gi-Oh! 5Ds has Jack realizing, through his interactions with Carly, that power isn't everything and it's possible for someone like him to be redeemed. After the Dark Signer Arc ends, he goes right back to being a power-hungry Jerkass who barely acknowledges Carly.
Neo Roanoke in Mobile Suit Gundam SEED Destiny is fully aware that he's a monster, and that what he does—brainwashingTykebombs into serving as Sociopathic Soldiers—is beyond the pale. Yet he never does anything about it, and continues on his way despite his doubts, convinced that it is too late to turn back now. It's only with the revelation that he too has been brainwashed that he turns around.
Meanwhile every time Shinn expresses doubt in what he and Rey and Durandal are doing, the other two either butter him up with something or try to guilt trip him.
Several times over the course of the Golden Age arc in Berserk, it dawns on Griffith just what atrocities he has to commit in order to achieve his dream. And each time, he buries it so that he can continue pursuing his ambition. It comes to a head during the Eclipse where he sheds his final tear for sacrificing his most loyal soldiers just before completing his transformation into Femto. And then he rapes Casca in front of Guts.
Attack on Titan uses the variation of having already crossed the Moral Event Horizon, to heartbreaking effect. After confessing to Eren, Reiner breaks down and admits that he isn't even sure whether the things he's doing are right or wrong anymore. But since he's already come too far, there's no choice left to him but to charge ahead and throw proverbial gasoline on the fire. He grimly accepts that he's a murderer doomed to a brutal, short life. Similarly, Bertolt's stoic exterior crumbles when he admits that he's done horrible things and states it isn't even remotely possible to apologize. Like his partner, he accepts that it's too late to consider stopping. While more subdued, Annie seems to also realize just how far she's gone — apologizing in horror to the corpse of a soldier, but later brutally slaughtering soldiers while hunting for Eren. When she finds herself cornered, she encases herself in a Crystal Prison to escape.
Hughie from The Boys has a moment of this when Butcher manipulates him into walking out on Starlight. She desperately begs him not to leave and calls out to him in tears, but Hughie is so angry, confused, and ashamed that he leaves her without looking back. As the narration from that scene puts it:
The strange thing was, he knew she was right. Without being sure exactly why, he knew he was making the wrong choice. But he dredged up what he needed to keep going. To put one leaden foot in front of the other.
The Life and Times of Scrooge McDuck uses one of these for maximum effect. After his greatest failure, Scrooge spends decades wandering the planet, building his fortune. When he finally comes home, his sisters (who abandoned him after his crossing the Moral Event Horizon) have gathered his family to greet him... but he storms past them, demanding they arrange for the people seeking donations to get away. Hortense, furious at the change in her brother, tells him he can either stop them from leaving or never see them again, at which point all and sundry walk out (a young Donald Duck giving Scrooge a kick in the ass for good measure). Scrooge, realizing how badly he's screwed up, is about to run after them... when he sees his Roster of the Rich and realizes he's the richest man in the world. The last panel shows him laughing in celebration... as his family walks away, leaving him Lonely at the Top.
Earlier, while he's looking for gold in the Yukon, he spends some time sitting on a mountaintop, enraptured by the scenery, and wondering if he should just give up his money-grubbing ways and live off the land... then he says to heck with that, and announces that he'd put an oil pipeline through it if it would make him rich.
Cassidy: Yeh do it an' yeh're one of the monsters...But yeh know what? Yeh wake up the next mornin' an' yer still alive...Yeh sort yerself out a bit...An' a wee tiny part've yeh starts to believe in a second chance. Jesse: An' then you do it again.
In issue 59 of Archie Comics' Sonic the Hedgehog, Sonic and Tails get trapped in a pocked dimension with Horizont-Al and Verti-Cal, who are now locked in eternal combat thanks to the events of issue 50. At the end, after Sonic and Tails win with The Power of Friendship, they give Al and Cal a speech about how they should go back to being friends. They briefly ponder this...then decide "Naaaaaaah!" and return to killing each other.
In Superman: Red Son, Pyotr at one point laments his own evil deeds, most notably having killed that universe's versions of Thomas and Martha Wayne. He even attempts to commit suicide while Drowning His Sorrows, but is saved by Superman. At one point Pyotr says something along the lines of how Superman makes him want to be a better person than he is. But once Stalin dies and Supes becomes head of the Soviet Union, Pyotr promptly goes right back to being a ruthless, scheming bastard who actively attempts to depose Superman.
One issue of Superior Spider-Man Team Up had SpOck's "Superior Six" plan utterly backfire on him with him realizing what he had done was horrible and that he's planning on quit being Spider-Man and turn himself in to The Avengers. However, when he encounters Namor and he former ruler talks to him about his problems... he knocks Namor on his ass, tells him to get out of his city and promptly swings away, proclaiming that he will still be the Superior Spider-Man.
In the Phoenix Wright Musical Project, the song "Decree of the Prosecutor" has Edgeworth go through one. He reflects on his actions and wonders if using underhand tactics in the court makes him no better than the murderous people he prosecutes. He eventually decides that it's worth it, because "every criminal earns his punishment,/ so [he's] always done all [he] could/ What's the harm in filling in the blanks to some extent?/ If it's for the greater good?/ Indeed. If the defendant is clearly guilty, then [his] methods, no matter how extreme, should not be an issue at all!" He then wonders if his true motivations are actually caused by his personal feelings of "pretentious piety", but dismisses the notion on the grounds that it's best to use extreme methods to ensure that other people are spared the pain of loss that he himself went through.
In Boys Und Sensha-do, this can be seen as applying to Miho's mother. At the end of the first season of the anime, after seeing Miho defeat her older sister Maho's until recently undefeated school, sighs and claps, signifying some degree of acceptance of Miho's style of tankery, even if it goes against that of the Nishizumi family. In the fic, however, she is still planning on disowning Miho, as she was in Episode 8, because of what had happened and because Miho now has boys on her team. She ultimately ends up disowning Miho in Chapter 7.
Dragon Ball Z Abridged subverts the original Funimation dub with Vegeta mentioned in the Anime section above. In DBZA, it's Goku who suggests that Freeza made Vegeta evil, but Vegeta insists he'd be evil anyway.
Played straight with Freeza after he becomes half the man he used to be. When Goku spares him some energy, he begins to ponder if he should turn over a new leaf.
"Naaaaaaaaaah!" *attempts to blast Goku one last time*
In Mega Man Reawakened, Robert seems to be paying attention to what Wood Man is saying about his anger issues, but when he goes to talk it out with Dr. Light he becomes enraged at things being hidden from him, resulting in a huge argument.
In Mega Man: Defender of the Human Race, Wily has one in the episode 11 epilogue as he realizes ProtoMan leaving was his fault. Then he decides it can't be entirely his fault and rages at Dr. Light.
Tiesel has one in episode 13 when he feels guilty for what the Conduit is making him do, but suppresses his guilt when he remembers the Conduit's threats against him.
"Get what? That you wind up with a mark because you do perfectly ordinary things you're already good at and love doing, instead of trying cool stuff which nopony's ever done before?" A long pause. "That's the dumbest thing I've ever heard!"
For His Own Sake: When Granny Hina learns just how hellish Keitaro's time running the Hinata Inn has been, not only is she remorseful, she rebukes Naru and Motoko for trying to drive his father away as well, informing them that they are to treat her family with respect. Unfortunately, she later slips back into seeing herself as the only one who understands the girls, and starts trying to manipulate everyone into doing what she wants again.
Film — Animated
The Onceler does this twice in the 1972 Animated Adaptation of Dr. Seuss' The Lorax. Once when the Bar-ba-Loots were sent away, and again when the Swomee Swans and Humming Fish leave. The latter instance segues into his rant from the climax of the book. The epiphany only sticks after it's too late to fix anything.
Every once in a while, I sit down with myself asking, "Onceler! Why are you a Onceler?" And I cringe, I don't smile, as I sit there on trial asking, "Aren't you ashamed, you old Onceler? You ought to be locked in hoosegow, you should! The things that you do are completely un-good!" "Yeah? But if I didn't do them, then someone else would!" "That's a very good point, Mr. Onceler."
The things you say just might be true It could be time to start anew And maybe change my point of view... Nah! I say let it die!
At the end of Kung Fu Panda, when Shifu apologizes for his mistakes in raising Tai Lung, Tai Lung appears genuinely moved for a moment or two... but then decides that he doesn't want Shifu's apology and continues his assault.
Lord Shen in Kung Fu Panda 2 spends most of the film thinking that his parents banished him from his homeland because they hated him. When he tells this to the Soothsayer, she reveals that they actually loved him to such an extent that having to banish him literally killed them. Shen seems genuinely moved by this for a few seconds before promptly brushing it off.
He gets another after Po destroys his cannon fleet, where he accepts Po is right about not letting the past define who you choose to be now. He chooses to continue attacking Po, leading to his death.
The Hunchback of Notre Dame: Judge Claude Frollo has one of these at the beginning of the Disney adaptation, when the Archbishop makes him realize that dropping a deformed baby down a well after killing its mother (in front of a cathedral, no less) is not a good thing to do. It lasts long enough for him to spare the child, then he reverts back to his Knight Templar self for the rest of the movie.
He seems to have one of some sort in the song Hellfire when he sings "God have mercy on her/God have mercy on me". True to the trope, immediately follows it up with "But she will be mine, or she will burn!"
In Final Fantasy: The Spirits Within, Well-Intentioned Extremist General Hein has a couple of epiphanies where he realizes what he has done as a result of his zeal for destroying the Phantoms but goes ahead with his firing of the Zeus cannon anyway, even though it kills him and many others on board the space station with him, and proves to be utterly unsuccessful.
Film — Live Action
Vader has at least one such moment in Star Wars before doing his Redemption Equals DeathHeel-Face Turn. When Luke turns himself in to the Imperials during Return of the Jedi, the two have a talk together where Luke tries to turn him away from The Dark Side. At the end Vader simply says "It is too late for me, son", hinting that he knows he's on the wrong side but he doesn't think he can go back at this point. Then, he takes Luke up to face the Emperor, knowing the Emperor's plans to corrupt Luke's soul.
Towards the end of Hong Kong wuxia film Duel to the Death, Ching Wan tries to convince an embittered Chinese lord against the plan that he made with the Shogun of Japan to betray China. It makes the lord think, but just a minute later he tries to backstab the hero, only to hit and kill his own daughter instead.
In Death to Smoochy, Rainbow Randolph decides that it is time to end his vendetta against Smoochy. He talks of "gracefully marching forward" and "admitting that the rhino has won." That is until he picks up a photo of Sheldon with his ex-girlfriend. Angelo's panicked reminder of his resolution falls on deaf ears as Randolf screams and curses that he's going to end Smoochy once and for all.
In Spider-Man 3, Eddie Brock has been exposed fabricating photos of Spider-Man committing crimes to win the staff position at the Daily Bugle. He's seen in the church, seemingly repentant as he admits to being "humbled and humiliated". Then he prays for God to kill Peter Parker, who exposed him. Then he becomes Venom.
In John Woo's Broken Arrow, Deakins kills a man by crushing his throat, then remarks, "I just realized something. I never actually killed anyone before. I mean, I dropped bombs on Baghdad, but, uh... never face to face." [beat] "I don't know what the big deal is, I really don't."
In The Bad and the Beautiful, we first meet Jonathan Shields at the funeral for his father, a former Hollywood big shot who died penniless after his studio went bust. Despite the fact that literally everyone at the funeral except himself was paid to be there and pretend to be mourning, Jonathan takes nothing away from the fate of the man he calls "the king of the heels," except that he'll have to work extra hard to ram the Shields name down the throats of everyone who didn't pay him in the proper respect. He then spends the rest of the movie being a bigger bastard than his dad ever was.
In Young Adult, Mavis Gary has to deal with the fact her high school boyfriend's actually happy with his wife and newborn daughter, and she herself has been behaving in an increasingly immature fashion; but just as Mavis says "I need to change", she learns a *very* minor character still considers her a winner, and her narcissism is once again fed.
In The Godfather Part II, when Michael returns from Cuba to be told that his wife had a miscarriage while he was gone, he starts to think about what's happened to his immediate family since he became don and talks to his mother about it, asking whether it's possible to be so focused on the idea of protecting your family that in the meantime, you lose them — basically spelling out the entire main theme of the three films. But his mother tells him that "you can never lose your family," and he's reassured that he's doing the right thing. Later in his confrontation with Kay, he tells her he knows they've been growing apart and that she blames him for the miscarriage, but they'll get past it: "I've learned that I have the strength to change." She tells him how blind he is; that it wasn't a miscarriage but an abortion, because she wouldn't bring another child of his into the world, which enrages him so much he forgets any idea of repairing the damage he's done.
Bluto's "Was it over when the Germans bombed Pearl Harbor?" rant in National Lampoon's Animal House and subsequent charge out of the house goes unreplied by the others in Delta House.
In Richard Adams' Watership Down, General Woundwort is offered an alternative to bloodshed by Hazel, and a chance to prove himself a "visionary" leader. He considers it for a moment, but then rejects it offhand in favour of his carefully planned destruction of the enemy warren.
Dragonlance Lord Soth has at least several of these during the Ravenloft novel Knight of the Black Rose.
The first, in his backstory, begins with Soth having just been found guilty at his trial. As he is carted through the city of Palanthas in disgrace, a mob angrily taunts him and throws fruit and rocks at the once heroic knight. One of them shouts "The Kingpriest is right! Evil exists even within the Knights!" This gives Soth a moment of remorse and reflection that he has provided just that proof for the fanatical Kingpriest, and about how this will allow the Kingpriest's Corrupt Church to strengthen its grip on the world... but then a rock hits him and he forgets all about that and goes back to angrily cursing the crowd.
After his escape from prison, Soth returns to his Tower, where the rest of the Knights besiege him. As this drags on longer, Soth becomes more corrupt and starts falling further and further from the hero he used to be. At one point, after an argument with his wife, he hits her. Looking at himself in the mirror afterwards, Soth realizes just how far he's fallen, goes back, begs forgiveness of his wife and the gods, and gets a divine vision of a Redemption Quest: to stop the Kingpriest from inadvertently causing the Cataclysm. Soth charges off on his quest... until he runs into a group that accuse his wife of being unfaithful, and Soth promptly charges right back, allowing The End of the World as We Know It so he can confront her about this.
After wandering into the magic border of Ravenloft, the Demiplane of Dread, Soth is presented with a vision of himself and what might have been if he had fulfilled The Quest above: himself with his honor restored, his dead wife by his side, and the son she was pregnant with there with him. Soth is told that if he merely repents and asks forgiveness from the good gods this might come true. Soth hesitates for a time, but his pride prevents him from doing so, and he instead fights the other version of himself, and kills his son when the son tries to interfere. An arguable case because we don't know what Soth was thinking while he hesitated, (the chapter is told through the point of view of another character), and there's a good chance it was a cruel joke on the part of the dark forces that control the demiplane.
The Scarlet Letter— in the middle, Roger Chillingworth realizes that his desire for revenge against Rev. Dimmesdale for cuckolding him has turned him into "A fiend!" Hawthorne's narration says that this sort of moral clarity sometimes only occurs to people once in many years. However, Chillingworth's long since lost any purpose in life other than revenge, and so continues down the path.
In The Case of Sergeant Grisha, Major General Schieffenzahn is briefly convinced to rescind the order for Grisha's execution (and has a What Have I Become? moment too); but a snowstorm prevents him making a phone call, and by the time communication is restored, he's abandoned his forgiving whim.
In the Spaceforce books, Jay is forcibly brought to the realisation more than once that his compulsive womanising may destroy his life, particularly as such behaviour is actually a criminal offence in the Taysan Empire. He does recognise this and vows to reform at the end of the first book - the very first scene of the next book finds him in a tavern, attempting to pursue a liaison with the serving wench.
Edward knows that stalking Bella in Midnight Sun is wrong and he even points it out to himself; he just doesn't care. For that matter, Bella tells herself dozens of times throughout all of the books that Edward is dangerous, Jacob is dangerous, she's in danger, she shouldn't be with Edward, etc. She never pays these revelations much mind, and goes right back to ogling Edward right after.
In Breaking Dawn, Leah calls Bella out on her selfishness. While everyone else jumps down Leah's throat for upsetting her, Bella admits that Leah is right. This realization is ignored by everyone, including Bella herself, who proceeds to continue being selfish anyway.
It's worth noting that this version of Raistlin was almost totally insane prior to this conversation, and seems to have snapped for good after learning of his fate. The main-timeline Raistlin, thankfully, subverts this trope.
In Bernard Cornwell's Saxon Chronicles the hero, Uhtred, spends the first couple of books as a violent, arrogant, murderous thug whose only real virtues are loyalty to his oaths and being one of the best fighters around. Half-way through the second book a prostitute tells him exactly what she thinks of him, and he's forced into something of a personal re-evaluation after which... he doesn't stop being arrogant, murderous and unfaithful to his wife. But he does start to feel a little guilty about it.
When Satan sees the beauty of Earth for the first time, he is deeply saddened and laments on how he used to be part of the beauty created by God, and that if he had been a lower angel, he would have been perfectly happy continuing to serve Him. Then he rejects the idea of repentance by concluding that any apology he gave would be insincere because he's gone too far into making evil his good, so he can't turn back.
When Belial suggests that if all the fallen angels just say they're sorry, God may let them back in. Mammon shoots down the idea outright, but suggests that they could at least try to make Hell into a nice place and live basically at peace with God. It's Beelzebub (on Satan's earlier advice) who convinces everyone to just go with evil and try to corrupt humanity.
In Terry Pratchett's Wyrd Sisters, Granny Weatherwax uses headology on Lady Felmet to show her all the evil she's committed. There's a moment when Felmet acts like she's about to pull a Heel-Face Turn, or at least a Villainous Breakdown, but she shakes it off and then says she knows exactly what she's done, and she likes it.
Also from the Discworld: The faculty members at Unseen University tend to dump unwanted tasks on younger wizard Ponder Stibbons, but they don't realize the extent of this behavior until Unseen Academicals, when he pulls off a one-man majority vote using his accumulated positions. At this point they finally realize what a burden they've placed on him and decide that someone has to do something about it. Three guesses as to who gets THAT job.
In Graham McNeill's Warhammer 40,000Horus Heresy novel Fulgrim, Fulgrim realizes he is committing a horrible crime when he fights his brother Ferrus Manus, but his sword convinces him to kill him. (Then it lets him realize it, so it can destroy him.)
Another novel reveals that Kharn the Betrayer went through this when a Loyalist tried to redeem him. The true reason he is so Ax-Crazy is that, deep down, he knows he's on the wrong side.
Jack Torrance has one of these in Stephen King's The Shining. In the chapter "The Snowmobile," Jack experiences a moment of clarity in which he becomes aware of exactly how the hotel has been manipulating him and turning him against his family. However, he keeps on thinking about the issue so intensely that he changes his own mind, concludes that everything is his five-year-old son's fault and that Jack himself is doomed whatever he does, and destroys the snowmobile, the family's one real chance to escape. It's worth pointing out that it's not just a case of him changing his own mind; as a result of its (very tangible, very unpleasant) influence, his thoughts take a different direction as long as he's not actually inside any of the buildings that make up the hotel.
Alice in Wonderland: "Alice often gave herself very good advice, but she very seldom followed it."
Harold Lauder, a highly intelligent but deeply disturbed teenager, has one in Stephen King's The Stand. Prior to the plague outbreak, he was a fat pimply high school outcast that embodied Wangst. After spending weeks living in Boulder, he manages to make a place for himself in the community. His work helping to bury bodies causes him to feel a sense of camaraderie with his fellow workers. At one point, one of the workers calls him "Hawk". Harold thinks the guy is making fun of him- calling fat, pimply Harold Lauder "Hawk"- only to realize that he isn't fat or pimply anymore. For a brief moment, Harold can see that all of that petty high school bullshit that he was carrying around was just that: bullshit. He goes home that day resolving to abandon his plans to betray the Free Zone and become an honest and upstanding citizen. Too bad the Big Bad sent Nadine Cross to seduce him back to the Dark Side.
Does it count if he didn't make the active choice to return to his old ways?
Years before becoming the biggest Knight Templar out of many in The Warlord Chronicles, Nimue was just a druid's apprentice who, for a single day, considered throwing magic and the gods aside, marrying the main character (who had been in love with her since they were just kids) raising a family and owning a farm. Considering that many years later Nimue's actions resulted in the death of Merlin, the betrayal of Arthur, the maiming of main character Derfel, the deaths of many of Arthur's most loyal warriors and thus, indirectly, Arthur's death at the hands of Mordred and the weakening of Britain's ability to resist the Saxons not to mention the misery these actions caused her, it might have been better if she'd done just that.
When Gandalf offers Saruman a Last-Second Chance, he genuinely struggles and seems perhaps on the edge of accepting before his Pride and jealousy of Gandalf cause him to refuse.
A shadow passed over Saruman's face; then it went deathly white. Before he could conceal it, they saw through the mask the anguish of a mind in doubt, loathing to stay and dreading to leave its refuge. For a second he hesitated, and no one breathed. Then he spoke, and his voice was shrill and cold. Pride and hate were conquering him.
Played with in Gollum's case. Seeing Frodo asleep at the top of Cirith Ungol, he teeters extremely close to a Heel-Face Turn, but goes right back to being The Starscream a few minutes later, but only because Sam wakes up and, in his confusion, abuses him as he always does. Gollum didn't take it well at all.
Tolkien loves these. In The Silmarillion we have Sauron's repentance before Eönwë at the end of the War of Wrath, which he then takes back when Eönwë asks him to return to Valinor to be judged. The last king of Númenor Ar-Pharazôn also has one when he catches sight of the Undying Lands, and momentarily hesitates before invading them.
In the Disney Fairies series, Vidia is infamous for plucking feathers from Mother Dove, whose molted feathers are used to make fairy dust. The first book, Fairy Dust and the Quest For The Egg, reveals that Vidia didn't enjoy plucking the feathers, but convinced herself that Mother Dove was making the pain seem worse than it really was. Later in the story, she has to pluck a feather from a golden hawk, who has the power to telepathically share its pain, and thus she feels what plucking feels like for herself. The narration points out that Vidia could have acknowledged that what she'd done was cruel, but instead she decided to believe the hawk had made the pain feel more powerful than it was to spite her.
Darth Bane has one when he realizes that he inadvertently killed his own father by unknowingly tapping into the Dark Side of the Force. His shock and guilt are strong enough to sever his connection to The Force, and he realizes that the Dark Side will ultimately destroy him. Unfortunately for everyone in the galaxy (especially himself), his desire for power overcomes this brief moment of remorse.
In L. Jagi Lamplighter's Prospero Regained, Eramus has repeated moments of this after some revelations. He gets called on it, frequently.
Sisterhood Series by Fern Michaels: Roland Sullivan from Lethal Justice is the personification of this trope! He started out as a relatively decent guy and family man. Then Arden Gillespie entered into the picture. He became addicted to her, and engaged in Your Cheating Heart. He helped Arden suck up all the money belonging to an elderly couple, causing this couple to be Driven to Suicide. Then, to cover up their crime, they frame Sara Whittier (AKA Alexis Thorne), their own employee for it! Sara is found guilty and imprisoned for a year. It is only when they framed Sara that Roland had a Heel Realization. He made no attempt to make it right. He lost sleep over it, forced Arden to set up some pictures of Sara in their offices (as a reminder of how low they sunk), and tried to spend more time with his family. He and Arden practically blackmail each other. He actually wants to find Sara to apologize to her...and use Buy Them Off on her. He still uses his ill-gotten gain to live the high life. He still cheats on his wife with Arden. Sure, his internal monologues claim that he has no willpower, but it seems that he just uses that to excuse his behaviour. His wife finds out that he cheated on her, throws him out and makes moves to divorce him. He actually tried to claim that he did all this for his wife and brags that he'll bring in lots of money and they'll all live the high life, but she rejects this, and points out that she never wanted to live any high life. She makes it clear that she knows that he and Arden framed Sara and urges him to do the right thing. He just blows that off. Later, he says to Arden, "I just realized something. You don't have a conscience, do you?" Arden simply retorts that it is too late to worry about something like a conscience. Roland is clearly a Horrible Judge of Character if he only made this realization at this late date. He makes no attempt to do the right thing or break away from her. He gets involved in another money-stealing scheme with Arden. Sure, he tried to refuse, but he still went and got involved. By the end, he gives off the attitude of a man who wants to get caught and punished. The fact that he has multiple instances just makes him very unsympathetic.
In the last book of The Wheel of Time, Demandred, the commanding general of the Shadow's forces, comes to the realization mid battle that he finally has everything he'd ever wanted- the love of a beautiful woman, an entire nation who revere him as a conquering hero, and the chance to (by switching sides mid-battle along with his followers) defeat the Shadow himself and become the world's savior. Unfortunately, he then decides that even if he did that, he'd never be happy until he killed Rand, the reincarnation of his hated rival. Needless to say, Demandred did not turn on the rest of the Shadow's forces that day, and remained a villain to his death.
According to Candayce this happens every time she or the other Wetherford bullies met Janine's eye and "soul-piercing gaze" in Dinoverse. They became aware of how petty and treacherous they were, how little integrity they had, but while this would distract them from what they were doing and keep them from doing anything to her, they never changed their behavior.
In Harry Potter and the Deathly Hallows, when Harry and the Dursleys are parting ways, seemingly forever, Petunia looks as if she's about to say something to Harry, then she simply... doesn't. A deleted scene from The Movie suggests what she might have been about to say:
You didn't just lose a mother that night in Godric's Hollow. I lost a sister.
Live Action TV
In the episode Dry Guys of Workaholics, the guys stop drinking for a while, and have a therapy session with their company's HR substance abuse rep. They have a real breakthrough-Adam realizes he's very selfish, Ders apologizes for being too controlling, and Blake admits part of the reason he's immature is he doesn't want to grow up and leave his friends behind. A few minutes later, the guys realize that being sober makes things too real, and they go right into a montage of drinking.
One of the sharper examples is Phil Leotardo, who wages a brutal turf war against Tony during the final seasons. Tony attempts to put an end to it while Leotardo recovers from a heart attack in the hospital, pleading that they could bury the hatchet and live long enough to see their grandkids, which moved Phil to tears. But ultimately Phil's anger and resentments overrode his willingness to compromise, with disastrous results.
Tony, of course, struggled constantly with the bad man that he is, and his therapy sessions often forced him to admit his faults. But his attempts at self-improvement never really take, and by the end of the show it's difficult to say that he's changed much at all.
Tony's sister Janice also saw a therapist for anger management, though her sessions were court-ordered. She seemed to being making progress at first, but Tony goads her into losing control basically out of resentment shortly after. By the end of the show, whatever stability and self-control she'd managed were completely undone after the murder of her husband.
Lindsay gets one in Season One's "Blind Date". He decides he can't let Wolfram and Hart kill some kids and so helps Angel and company save them. Naturally, his bosses were aware of it, but they know him, and with the offer of a promotion, a raise, and "ungodly benefits", he ends up joining them again.
Lindsey resigns for good in Season Two, ironically after having earned a top position and a replacement hand to boot; he leaves Los Angeles, burying the hatchet with Angel for good. ...Or not. Actually, he was studying for years on how to join the elite Circle of the Black Thorn.
Angel's epiphany, from the season 2 episode "Epiphany", is completely forgotten for the entirety of the season 5 arc.
Harmony fondly remembers high school, and desperately wishes to be accepted by friends that way again. Unfortunately, Harmony self-sabotages every friendship she has due to being Stupid Evil.
Brutus, sort of, on Rome. In late season one he feels only betrayed by Caesar and gives in to his mother, going along with the plot to kill the dictator. He goes through with it, but then Antony comes in and they share a look where Brutus' guilt is written all over his face. He then cries out in agony over what he's done. However he seems to get over it rather fast, and stays allied to Cassius to the very end.
This is a common issue in works based on Real Life. Authors and audiences want to see deep moral conflicts in the characters, and see them doubting or guilty over the things we feel they should be doubting or guilty over. Of course, the problem is that the real characters may not have felt that at all — so we get fictionalized versions that show great doubts and agonizing self-evaluation in private, then instantly go back to behaving like it never happened when the story continues to follow reality.
Then again the fictional character Brutus in this case might just be falling back to the sunk-cost fallacy.
Towards the end of the second series, as Atia accuses Octavian of being a monster, this is very subtly done with the look on Octavian face. One wonders whether at that moment he has a Heel Realization moment, but ultimately he goes on, business as usual.
In a classic Saturday Night Live sketch, after a series of superstitious medieval trials, Steve Martin goes on a monologue laying out a better way to determine guilt, describing a modern American jury trial. He then immediately discards the idea.
This "Nah!!" bit was a Running Gag on SNL in the early years, especially for Martin. See ''Theordric of York, medieval barber-surgeon" for another example.
Lampshaded on an episode of The Fresh Prince of Bel-Air. Will is blackmailing Hilary because he knows she dropped out of school and plans to make her do humiliating things at dinner:
Hilary: Will, if you have an ounce of compassion, you'll let me off the hook. Will: That's a good point. (pause) Nah! We'll do it anyway!
Lampshaded in Wizards of Waverly Place where Alex comments on having got a weird warm and fuzzy feeling after helping Hugh Normous and upon learning that this is what happens when you do good comments that it's not bad, but that she doesn't plan on making a habit of it.
A couple of times in the Doctor Who episode "Last of the Time Lords", the Master seems to almost listen to the Doctor's advice, only to go ahead with whatever he's planning.
The Doctor himself has a somewhat unintentional example in the series six final. After the Doctor learns of The Brigadier's death, one of his oldest friends in the show, this event shows him clearly realizing and accepting his own mortality only to reject it again when he find a way out
Naked Chef's Jamie Oliver showed a group of AmericanWest Virginian school kids the basically inedible chicken parts go into their McNuggets and they still wanted to eat them. A follow-up article revealed the kids also rejected his healthy lunch for their usual pizza and soda, although they said they'll still try new foods so I guess that's something. (Then again, the fact that we decree any part of a chicken inedible, when one clearly can eat it, is more than a little elitist.)
An episode of Everybody Loves Raymond had Frank and Marie living in a retirement home, and almost immediately getting kicked out. Despite the home giving a full list of complaints against the two of them, the pair blamed each other and guilted Robert and Amy into giving up their home, which they paid for, so they could live there again.
Londo Mollari from Babylon 5 comes to have doubts about both the political games he is playing with his co-conspirators on Centauri Prime and the alliance with The Shadows before being involved with them for long, but resolves to keep going, saying that it is too late to turn back now.
Londo: I have made many choices lately, Vir. And today, for the first time I am not sure those choices were right. Vir: Perhaps some good has come out of this tragedy. It's not too late to make some new choices. Londo: No. The blood is already on my hands. Right or wrong, I must follow the path to its end.
Oswald Danes has one in the final episode of Torchwood: Miracle Day when exposed to the Blessing. He first seems headed to a Villainous BSOD when forced to confront his (child molesting, murderous) soul. He snaps right out of it, though, apparently enjoying this evil revelation.
Herod to Herodias in Franco Zefirelli's Jesus of Nazareth: "He (John the Baptist) is right, you know. We have sinned... And we go on sinning. And very pleasant it is, too! Repent! (kiss) Repent! (kiss) Repent!"
Frasier is practically the king of this trope. It's easy to lose count the number of times Frasier and/or Niles openly recognize and come to terms with one of their faults only to almost immediately turn things around and go back to the way they are within seconds.
On Breaking Bad, Jesse has a profound Heel Realization in rehab, but quickly returns to the meth business. It seems to be more out of inertia than anything else; this is the only skill he's ever bothered to develop. But his conscience continues to eat at him — unlike Walt, who quits cooking a number of times, but never for that reason. As of the second half of Season 5, it appears to have kicked back in full force, after he witnessed a child murdered by one of his colleagues. He now wants nothing to do with the meth business and even throws and gives his $5 million away like candy.
One episode of Malcolm in the Middle involved Malcolm and Reese realizing they are the least popular kids in their school when literally every other student decides to skip class one day, and nobody told them to do it too. Infuriated, the two try to figure out what everybody has against them. At one point they realize that hey, maybe it's not just that everyone is out to get them, and everyone just hates them because they're both huge Jerk Asses -Malcolm through his superiority complex and Reese through his bullying- but this is quickly shot down in favor of They're Just Jealous.
In the Law & Order: Special Victims Unit episode "Selfish", the small child of a young, irresponsible mother dies after contracting measles from another child whose mother refused to vaccinate. After the anti-vax mother is found not responsible for the other child's death, the detectives convince the victim's mother to let go and start taking responsibility and reform herself. And then she leaves the station with her angry, aggressive mother and weak-willed, brow-beaten father, after which her mother "sets her straight" and convinces her to take revenge on anti-vax mother.
24 has a tragic one late in the series. Alison Taylor, who up to this point has been the Big Good on the show, has ultimately allowed the masterminds behind the attacks on New York earlier in the day to go free in exchange for them signing a peace treaty. One episode later, her adviser Ethan gets her to realize she's just sold out her morals. But seconds before she's able to act on this Former PresidentLogan is able to convince her that it's a necessary evil for the greater good, and she ultimately allows the coverup to continue. What really makes this a punch to the gut is had she not ignored her previous judgement not only would she likely have been able to salvage her political career like Ethan suggested, but Jack could possibly have been called off his Roaring Rampage of Revenge before he crossed the line and became an international criminal, a rampage where her agreeing to the coverup had been the deciding factor.
Since I was no bigger than a weevil, They've been saying I was evil That if bad was a boot, that I'd fit it That I'm a wicked young lady, But I've been trying hard lately Oh fuck it! I'm a monster! I admit it!
Actor/comedian Denis Leary gives us the first page quote from his song Asshole, a satire and skewering of the American middle class. Throughout the song its main character talks about how, despite all the things he has, his true joys come from a near endless series of petty cruelties he inflicts on the people around him and general self-centered douchebag behavior. Around the middle of the song he considers the idea that maybe this truly is wrong, but, as seen in the quote, his response is "Nah!"
Voltaire's "When You're Evil". After a long gleeful litany of varying acts of nastiness and reveling in his Evil cred ("The Devil tips his hat to me") , the narrator appears to waver and mournfully, (albeit selfishly) sings "It gets so lonely being evil..." but then snaps right back, and furthermore claims that his moment of weakness was just a lie to mess with your head. Played rather well in thisLabyrinth fanvid.
And for what? I've killed and I've shot And reddened the cold tears of children with blood And If I could go back and make my amends I'd make all those mistakes again I'd kill every last one of those bastards, my friend
I am not a bad man Even though I do bad things Very bad things Such horrible things But it's not quite what it seems (Not quite what he seems) Not quite what I seem... Ah, Hell... It's exactly what it seems.
In The Megas' second album, "History Repeating:Blue" Dr. Light gets a song that's a Dark Reprise of one of Wily's songs from their first album, "I Want to be the One (To Watch You Die)". In it, Light seems to wonder at one point if what he's done isn't so different from Wily, and he expresses remorse for turning Rock into a weapon against his rival. He then decides it doesn't matter, Wily needs to die, and Light wants to watch it happen.
At the end of Hope Rides Alone by The Protomen, the citizens are asking questions like "what have we done?" and "where did we go so wrong?" They then do nothing whatsoever to act on this.
In Warhammer 40,000, this is the hat of the Dark Eldar — they deliberately continue the nightmarishly hedonistic ways that brought their civilzation to ruin, primarily because they'll be utterly destroyed if they don't.
After the scene in which Banquo's ghost memorably interrupts his feast, Macbeth has a quiet one of these. In the end he winds up deciding that it would be as bloody and dark a path if he were to turn back on his ambitions then as if he were to go forward, so he keeps going and soon after jumps completely off the slippery slope.
"I am in blood stepped in so far that should I wade no more, Returning were as tedious as go o'er."
William Shakespeare is fond of this trope. He also uses it in Hamlet, where Hamlet's Evil Uncle has a moment where he realizes what a truly evil and unforgivable thing he's done by killing his brother and marrying his brother's wife. He even realizes that repenting is useless as long as he still profits from his act, so he prays for the strength to give up everything he's gained. When he finds he can't do so, he abandons any thought of repenting and just does his best to hold onto the throne.
Richard III has his worst moment when the ghosts of his victims plague him in a nightmare. He shouts for mercy. But in the morning he declares that conscience is a fraud "devised to keep the strong in awe. Conscience, avaunt!"
In Eugene O'Neill's Long Days Journey Into Night, the characters are trapped in their past behavioural patterns, most notably Mary with her morphine addiction and James with his alcoholism and hurtful tongue.
Mary: The past is the present, isn't it? It's the future, too.
In Oliver Fagin, while "Reviewing the Situation," considered going straight and the situations it might result in, but finally decided:
I'm reviewing the situation. I'm a bad 'un and a bad 'un I shall stay! You'll be seeing no transformation, But it's wrong to be a rogue in ev'ry way.
Kratos has one in the first God of War game, when he sees a pile of soldiers killed by the followers of Ares, and has a flashback to making his bargain with Ares. At the end he whispers "What have I become?" but then promptly forgets about it. Of course, the gods keep screwing him over, and at one point in the second game he says that he's what the gods have made him.
He says this again, word for word at the end of Ghost of Sparta, after killing Thanatos and burying the bodies of his mother and brother, the gravekeeper simply looks to him and responds, "You have become Death."
Arthas in Warcraft III: The Frozen Throne has one of these when he climbs up the steps towards the titular throne; he hears the voices of his former teachers and friends scolding him, warnings that he is making a terrible mistake. Then the Lich King commands him to return the blade, so Arthas does, striking the Frozen Throne so hard that it shatters and releases the armor trapped within. Then Arthas puts on the armor, fusing his and Ner'zhul's souls to become a new Lich King.
The voice of the Prophet saying "Your young Prince will find only death in the cold north" is heard but Arthas wasn't present when he said this nor did he meet the prophet again.
Both Atris and Kreia have several such epiphanies throughout Star Wars: Knights of the Old Republic II and decide to continue their evil ways just the same. "It is such a quiet thing, to fall. But far more terrible is to admit it." Both characters then proceed to attempt to bring about the Annihilation of All They Hold Dear, proudly proclaiming how wrong they were about everything when they force the protagonist to kill them. Depending on how things play out, Bastila may have met a similar fate in the first game.
Ryan of BioShock has a very brief moment in one of his audio diaries where he admits that Rapture has gone straight down the tubes and it's pretty much his fault, only to go right back to his old ways.
Dragon Age II gives us the final boss of Knight-Commander Meredith. During the battle, at one point, all allies and enemies will become stunned, and she will ask how such evil can be so powerful. She then wonders if she is wrong, that everything she is doing is madness. She then hardens her resolve in her next statement, and says she must hold fast to her convictions, and the battle continues.
Anders apparently has one, but most of it is off-screen between Acts II and III. He tries to put his obsession with the mages' plight aside and learn to reign in Vengeance. If he actually killed the mage he rescued during his personal quest, he outright calls himself a monster. Yet, by Act III, the obsession is back. And its much, much worse.
Near the end of Portal 2, GLaDOS is terrified that the voice of conscience she hears is her own voice for the first time. After the final battle, she locates the Caroline subroutine responsible for it and unceremoniously deletes it.
Word of God states that this is exactly what was intended. GLaDOS learns a lesson but chooses to reject it, and Wheatley learns a lesson but is in no position to repent.
Final Fantasy XIII: when Hope details Operation Nora for Lightning, she realizes that Hope intends to kill Snow out of revenge for his mother's death (which really wasn't Snow's fault). Lightning tries to talk him out of it, but Hope is Genre Savvy enough to know that revenge solves nothing. He just doesn't care, and wants to kill Snow anyways.
Gehn from Riven decided that the number five was the Arc Number essential to the art of writing Ages. All the evidence pointed to said number actually being six, but Gehn refused to acknowledge this. It didn't end well.
One genuinely heroic example in Fate/stay night: Unlimited Blade Works. When Shirou finds that his ideal and way of life are distorted after being challenged about them by Rin, he logically realizes that his processes are wrong. However, he also decides that he won't listen to her warning, because:
Shirou: There's no way that wanting to help people can be a mistake.
The villain of the second arc in Shikkoku No Sharnoth realizes he's in the wrong and that happiness is just in front of him if he just stops, but in the end he is just too insane to do it.
In the Meakashi-hen arc of ''Higurashi: When They CryShion brutally kills Satoko and remembers that the last thing her disappeared boyfriend Satoshi had asked of her was to protect his little sister. At first, she's horrified... but then she figures 'Eh, too far gone anyway, might as well continue to be a psycho. Of course, the next arc shows that perhaps it really wouldn't have been too late.
In three of the four "true" endings of Nicole, the kidnapper is momentarily shaken by the way the other potential love interests refute his reasoning for kidnapping the people he did, but he quickly shrugs it off and continues being a Smug Snake. In his own ending, he subverts this and has a Villainous BSOD instead.
Happened once or twice to Black Mage of 8-Bit Theater; he realizes that White Mage might actually like him if he stopped being an evil jackass. Then Fighter started talking and it all went stabways.
In fact, BM is probably past the point where epiphanies have any chance of changing him — because at least once, he saw one coming and took measures to "protect" himself from it.
Parodied in No Need for Bushido when Ken threatened to have a moral epiphany and stop mugging strangers if the rest of the group doesn't help him perform a play for his favorite Kabuki actor. Since this is the only source of income for the group, Ina quickly agrees, only for Ken to immediately tell her he never planned on going through with his threat in the first place.
There's also Belkar, who Vaarsuvius uses Owl's Wisdom on to grant him the ability to use healing scrolls. That wisdom gives Belkar the chance to reflect upon the good he could do by devoting his life to healing instead of killing, then Vaarsuvius dismisses the spell, with Belkar reverting to his old self.
Later on, a half-dead Belkar has a genuine epiphany, as he realizes that being a blatant murderer and psychopath is eventually going to get him killed by one of the genuinely-good guys. This does not convince him to turn away from evil, however — he just realizes that he has to learn how to fake being on the same side as the rest of the team. And it works.
Of course, the leaders of his genuinely good-guy group see through it immediately, but play along as it means that the little psycho would be easier to control for the remaining months of his life.
Weary of being a slave to these homicidal impulses, Butch seriously considered getting a lobotomy. But for that he'd need a referral from his Primary Care Physician, whom he'd buried under the back porch last Tuesday. Damn HMO.
In Dominic Deegan, Bulgak the Orc Infernomancer keeps insisting that "(he) is good person", despite Infernomancers being evil by the very nature of their powers (they sell their souls to their patron demon in order to channel that demon's power) and Hell itself showing him the evil that he's done.
He does get over it, and, surprisingly, is apparently Easily Forgiven by the powers-that-be when he makes the actual epiphany, but it takes way longer than it probably should.
An inversion from Girl Genius where the character isn't as bad as the semi-sarcastic self-description she delivers...but goes along with it anyway because it's useful.
Agatha:I'm the bad guy, because, for whatever reason, you didn't tell your nasty little friend who you are. And now she's sad. So you're mad at me—because now she's all teary and sweet and needs rescuing. And I'm the evil madgirl with the deathray and the freakish ancestors—and the town full of minions—and the horde of Jagers—and the homicidal castle full of sycophantic evil geniuses and fun-sized hunter-killer monster clanks and goodness knows what else...and you know what? I can work with that!
In Errant Story, Ian has this realization, but his attitude is pretty much "Aw, shucks," and he continues on his plans of genocide:
"Oh, dear Lord, I actually have zombie minions. Yep, I guess I really am evil now."
One Least I Could Do story arc made it look like Rayne might come to terms with his skirt-chasing after learning that he blew his chance with his hot boss Marcy because she moved on after spending years waiting for him to make a move. But then he gets over it by hanging out with his niece, and by the next week's strips he's back to being a man-whore.
Bobby Jacks of Survival of the Fittest. He quickly comes to the realisation that he's one of the bad guys, but immediately after he decides that he's gone too far to try and repent. He even supplements this with a quote from Macbeth (the exact same one which Macbeth himself uses in this selfsame situation).
Snake has one of these at the end of this hilarious flash video.
One way of looking at Dr. Horrible's final song has elements of this. The song plays with double meanings that underline the tragedy of the scene, most importantly the first, "Here lies everything/The world I wanted at my feet." Arguably, Horrible acknowledges here that everything that has just happened is (at least partially) his fault, and Penny is dead because of his recklessness and his drive to join the Evil League of Evil. They offer him a place, though, and he accepts, even though he hasn't forgotten his loss.
In A Very Potter Musical, Harry tries to convince Voldemort that he regrets his evil deeds, and sad music starts to play...
John Cheese on Cracked recounts how he was asked to be best man at his friend's wedding where they wouldn't have alcohol, and began to grow anxious and irritable because of not being able to drink. Eventually he cut his toast short and made up an excuse to leave early so he could drink. He realized that he was actually afraid of going without alcohol.
This realization is what motivated me to, uh, completely forget about it and continue drinking for about eight more years.
Even though The Nostalgia Critic has a barrel-ton of Guilty Pleasures himself, when it comes to a movie he sees no good in (like the Jim Carrey remake of How the Grinch Stole Christmas!), he never fully comprehends how others can like it. In the specific case of the Grinch movie, at the end of his review he contemplates taking a more tolerant, open handed view and saying that if people take pleasure in it or see something in it that he doesn't, then maybe that's what counts... then essentially says "Nah, I'm right, they're wrong!"
Frieza in Dragon Ball Z Abridged had two of these, against the completed Spirit Bomb and later when Goku gives him power after Frieza nearly dies. The first time he remembers all of the atrocities committed by him and in his name, concluding his greatest regret is dying. The second time he muses that maybe his selfish actions are wrong, before deciding "Nah!' and trying to kill Goku.
In Adventure Time Lumpy-Space Princess erroneously becomes convinced that her new boyfriend Johnny no longer has affection for her and is instead interested in Princess Bubblegum despite being informed that the meeting was strictly business. She speaks as if she will accept his "betrayal" and talks about how letting someone you love go into the arms of another takes a big person. She then says "I don't know if I can be that big." before throwing a bottle of gasoline into a nearby truck and crashing it into the castle, causing a huge fire.
By the season two finale, Zuko improves his life by listening to Iroh, adopts a positive outlook and more or less giving up his chase for the Avatar. Then Azula arrives and gives Zuko the chance to capture or kill the Avatar together, which would finally restore Zuko's reputation and allow him to return from exile. Zuko almost listens to Iroh's plea not to listen to Azula and join Aang's quest instead, but Azula's Breaking Speech convinces Zuko to join her attack on his uncle and the Gang.
He has another one in "The Beach," wherein Zuko has to come to grips with why he's still so angry and unsatisfied after returning to the Fire Nation. Despite having everything he's ever wanted he's still not happy, and after being pushed he realizes that what he's really angry at is himself, and the reason why is because he doesn't even know the difference between right and wrong anymore. (After all he's been steering his whole life around the idea that right meant being a good Fire Nation patriot, soldier, and a loyal son, but now he knows his country and father are on the wrong side of the war and about to commit genocide). Then he reconciles with Mai and continues to go along with things in the Fire Nation for about another half dozen episodes before finally doing his Heel-Face Turn for real.
In the same episode, Azula herself has one just before Zuko does, where each of the Five-Bad Band is sharing some hidden aspect of themselves and their flaws. Azula's is how she resented how their mother, Ursa, lavished attention on Zuko, and her perception that Ursa considered her a monster. She then wraps it up with "She was right, of course, but it still hurt!" This epiphany came back with a vengeance in the series finale, alongside a Villainous Breakdown.
Lao Beifong, Toph's father, witnessed her true power in the climax of "The Blind Bandit" when she took down seven master Earthbenders without taking a single hit or breaking a sweat. He saw her do things even her "teacher" Master Yu was astonished by. Recognizing her power and abilities, he promptly grounds her and tells her she won't ever be without escort; all to protect her from the world. Toph ran away that night.
A sad case in Moral Orel's "Grounded". Orel undergoes a near death experience to talk to God, and the resulting Dream Sequence grants him a profound epiphany about his faith. Then his father spanks him until he forgets it.
On The Simpsons, Mr. Burns experiences one in "Rosebud" after Maggie returns his beloved childhood teddy bear, asking Smithers to write down that from now on, he's only going to be good and kind to everyone.. Smithers realizes that he doesn't have a pencil and Burns responds "Eh, I'm sure I'll remember it."
Demona on Gargoyles gets one at the finale of the epic four-part episode "City of Stone". At the prompting of the Weird Sisters, she comes to the realization that all the events in her descent into villainy could be laid at her own feet, thereby shredding her justification for her genocidal hatred of humans into tiny pieces. After the Sisters stop talking, though, Demona angrily proclaims that she was tricked into saying that and has to be restrained by magic, leading Goliath to lament that she has learned nothing. Demona's still a villain the next time we see her.
Demona is made of this trope. Earlier in "City of Stone", in the earliest part of Demona's Start of Darkness, when her first plan goes wrong, she reacts to the death of her clan and the permanent freezing of Goliath and the others in stone by saying "What have I... what have they done to you?!!" In a great Call Back, at the very end of the series John, (a human hunting gargoyles) accidentally shoots his brother while trying to kill Goliath and says the exact same line.
Xanatos in "The Price" imprisons Hudson for a scheme, and quickly finds himself subjected to Armor-Piercing Question after Armor-Piercing Question about what he really wants. Near the end, Hudson asks Xanatos what his legacy will be when all his scheming is done. Xanatos seems disturbed by this...and then goes back to seeking immortality. Word of God, however, confirms that this did have a bigger impact on him than he himself realized at first, and later came to terms with his own mortality and found peace with death knowing that his immortal son would carry on his legacy.
Happens again in the appropriately titled "Mad Love". The Joker crosses Harley's Moral Event Horizon when he throws her out a window for upstaging him when she placed Batman in a Death Trap as a gift to the Joker. As the episode ends Harley is back in Arkham, badly injured but looking saner than ever before in the series. Her expression is serious, her crazy grin gone, and her inner monologue shows that she now knows that the Joker is "a murderous, manipulative, irredeemable -" And then she sees a flower and "Get Well" card the Joker sent to her. "-Angel!" And the insane grin returns.This is entirely in character.
In Pinky and the Brain: a psychologist determines through hypnotism that Brain's desire to rule the world was actually created in him subversively and accidentally by the scientists at his lab. What Brain really wanted was to go back to his family, who lived in a can with a picture of the world on it. But his mind was warped by the experimentation to the point that all he could remember was his desire for the image. Brain considers the possibility, but ultimately dismisses it and goes on as planned.
This trope, along with Never My Fault, is one of the many traits of a sociopath, since it is nearly impossible for them to feel guilt; even if they do, they tend to sweep it under the rug.