- MAG ISA — Eman's Dad regrets killing his wife. Then... he hangs himself later.
- The Order of the Stick has a rare villain example, where The Dragon Redcloak comes to regret using hobgoblins as cannon fodder because of his prejudices. "Oh my God... I'm turning into XYKON! What have I let myself do?"
- In the prequel book Start Of Darkness, Redcloak goes through a more tragic use of this trope after he kills his brother.
- There is a more obscure example in this strip; after Xykon uses a Symbol of Insanity to cause all the paladins to massacre each other, the last one standing recovers and cries, "Oh Twelve Gods... what have I done?" then commits
seppukuwhatever Azurites call ritual suicide.
- Vaarsuvius's expression upon realizing the Familicide spell killed off Girard Draketooth's entire lineage is the non-verbal epitome of this trope. V has a verbal one in the next strip at the discovery of just how many people Familicide killed due to the way the spell works.
- Very early in the strip, Elan pretends to be a wizard and spouted many nonsensical words. Vaarsuvius flips out and harshly insults the bard, causing him to run away crying. Immediately, Vaarsuvius feels awful, and Haley wastes no time chewing the elf out. The two make up in the next strip.
- Irregular Webcomic!: Han Solo's gun goes off accidentally, killing Greedo.
Han: Greedo, old pal! Are you okay?! Greedo? Don't fool around with me, buddy... Oh no!!!
- In Girl Genius, it appears that Prince Aaronev Sturmvoraus seems to have had one of these as his daughter is dying, if Tarvek's flashback is accurate. Of course, considering that she is in this condition because he had just tried unsuccessfully to overwrite his daughter's mind with the mind of his Evil Overlord / possible lover, the sympathy one might feel for him is abated some.
- In Thog Infinitron, the aliens (Opians) that gave Thog his powers finally realize that Thog's cybernetics are not inborn, and are in fact due to their medical intervention to save his life.
Tertaladrol: We're going to be sent to the dung mines of Guanolon IV, aren't we...
- During the Great Outdoor Fight arc of Achewood, Ray is attacked by country-western singer Cody Travis, and retaliates by ripping his face off. In the following strip, he looks at his blood-soaked hands and vomits.
- In Ask Axe Cop 15 after Axe Cop mistakenly kills a good guy.
- Done (to a degree) in response to Internet Backlash about Sixx drugging Laura without her knowledge in Collar 6.
- Bob and George After confessing. So to speak
- Sinfest's Monique learned that she may be responsible, in part, for the damnation of a million men.
- Seymore goes through this when a girl-turned-devil he wanted to truly reform finds his shotgun and goes on a rampage.
- Lil Evil asks this more literally than most. Having drunk from Lethe, he fears Amnesiac Dissonance.
- Baby Blue destroys many of Fuchsia's things -- and realizes.
- An ad offers apathy as a cure for this.
- Even the cartoonist has one of this, after realizing how much misogyny, racism, homophobia, etc; he has drawn for pure shock value and cheap laughs over the years.
- Dominic Deegan: What have I done?
- In 8-Bit Theater, White Mage has a moment of this trope after attempting to become evil
- In Strays, when Feral realized he was trying to choke Meela. (He had pushed her out of the bed earlier. With this, he goes and sleeps in the corner.)
- Pibgorn Pib. . . What have I done? (Why, lost Pib in the upper atmosphere when you need her help to save the earth.)
- Vriska in Homestuck goes through this when she realizes that her actions have resulted in the deaths of most, if not all, of the people she ever considered friends.
- Terezi has two examples: once in a subdued manner ( in a dream chat with Aranea over her decision to kill Vriska) and later on says the phrase word for word ( when Gamzee snaps out of his mind control in the midst of her very bloody Big Damn Heroes moment against him and begs her to stop stabbing him).
- Sluggy Freelance
Riff: Thanks to all the damage you did to the truck, we've lost another day! Instead of being able to free Torg and ZoŽ under the cover of daylight, we'll be lucky to make it in time at all. And that doesn't bother you."Bun-bun: "Nope."Riff: "Now we'll never make it home in time for the season premier of Baywatch..."Bun-bun: What have I done?"
- Parodied in "Vampires".
- Happens in a subtle manner when Torg realizes that he messed up the security computer systems and released a bunch of bad stuff. Torg was inside the No-Fun lab and blew up their server. This causes a bio-weapon mutagen to be released. This may or may not cause turn the entire dimension into a hell like realm full of demon like creatures
- Occurs again later when Riff says that future Torg will do bad stuff like cause the Research and Development War or turn this dimension into hell. More like "what will I have done", but still.
- In American Barbarian, Rich realizes what his pursuit of revenge did.
- Panthera's Jason has developed a tendency to slip into this. To be fair to him, he talked his boss into giving his little sister the same shapeshifting powers he has himself... only for things to take a sudden turn for the worst when Ari reveals that he's the very man they have been trying to hunt down and attempts to kill them. The one who kills him off is Onca/Taylor, who utterly freaked out four days earlier at the very idea that her big brother might have killed a person. Ten days after that, they find out that some of the world's leading scientists have no idea how they're still alive and they're going to wither and die in less than thirty years. Cut to the North Korea story arc, where Gyeoknoho comes pretty damn close to finishing his sister off partially because this time, Jason has no idea how he's supposed to come up with a plan to eliminate it. Is it any wonder that Jason is skirting the edge of Heroic BSOD right now?
- Part 1 of the Penny Arcade story arc Ripped From Today's Headlines has Tycho feeling bad for accidentally killing his wife.
- In Commander Kitty, the de-programmed Fortiscue has this reaction once he realizes what his creation has done.
- In Oglaf, a bunch of villagers approach the Thaumaturge asking her to save them from an evil army of Jerkass goblins. The Thaumaturge claims that evil is relative but jerkassery is not, so she agrees to help them. After the Thaumaturge has incinerated the goblins, the villagers react in a way that makes her realize that they were the true jerkasses all along.
- In El Goonish Shive, after Abraham is persuaded by Nanase that Ellen is a person not a monster he realizes he got very close to killing an innocent person.