In a lot of fiction it seems like everything, including outright backstabbing, is Easily Forgiven. But not in this case. In this case there is someone who just will not let something go. They really hold a grudge, deserved or not, for far longer than is reasonable for the offense or practical for the situation they are in. Everyone else in the cast might have gotten over it after a few episode or chapters, but this person has their feet dug in on the matter, and no amount of reasoning with them will convince them otherwise. Even if shown evidence that someone is reformed, is trying hard to atone for the hurt they've caused, or even if it's found that the offense was an outright accident, they still won't forgive. In retaliation they might give the offender the cold shoulder, or just keep bringing it up. They might even try to kill him. And this can be for anything, from bringing about the death of a loved one, to leaving the toilet seat up. Whatever it is, there is someone, maybe even a group of someones, who just won't let it go. The Inspector Javert is like this about an imagined crime. Compare Reformed, but Rejected, in which the reformed person is falling prey to this trope, as well as Cavemen vs. Astronauts Debate, which is a debate between two characters which invokes this trope, and Never Live It Down, in which characters in a show blow one thing another character has done way out of proportion and use that to define the character unreasonably, resulting in Flanderization. Contrast Easily Forgiven, this tropes polar opposite polar opposite. When the person who the grudge is held against doesn't remember, either because they do so many bad things it gets lost in their memory, or the thing done was so insignificant and unmemorable as to make the grudge itself ridiculous, is can result in But for Me, It Was Tuesday.
- In Scrubs every once in a while JD will throw the fact that he caught Turk in bed (literally in a bed, we don't know if they were actually doing anything or not) with his girlfriend of the time. Turks insists there was an innocent explanation but JD won't let it go.
- On Seinfeld there's George's "He's a step skipper! He skips steps!" behavior toward a recovering alcoholic who once slighted him at a party.
- María la del Barrio spent 7 years looking for her lost son, and ignoring her husband Luis Fernando. He eventually cheated her with the maid Penélope, and they were just about to divorce, but María forgave him. A new Time Skip goes 7 years to the future, when María finally finds her son. Still, she does not tell Luis Fernando about it, and when he discovers that she's meeting with a guy, he thinks that she's cheating him. María points, in the middle of their heated discussion, that he had once cheated her, and she forgave him.
- In The Dark Elf Trilogy, Roddy McGristle is constantly after Drizzt because the latter killed one of Roddy's dogs in self-defense. And also because a missed ax-swing at Drizzt caused a tree to fall on Roddy and hideously scar him.
- "Binky stole my joke!" - Buster Baxter
- Buster told Binky a Sphinx-related joke that he was hoping to use to get a good mark on his Egyptian history report, and then blamed his bad mark on Binky when Binky told it to the teacher, not aware of the intent with which Buster mentioned the joke. Buster rants about this throughout the episode.
- The Simpsons played with this when Marge developed a gambling addiction.
Homer: You know, Marge, for the first time in our marriage I can finally look down my nose at you. You have a gambling problem!Marge: That's true. Will you forgive me?Homer: Oh, sure. Remember when I got caught stealing all those watches from Sears?Marge: Hmm.Homer: Well, that's nothing, because you have a gambling problem! And remember when I let that escaped lunatic in the house 'cause he was dressed like Santa Claus?Marge: Hmm.Homer: Well you have a gambling problem!Marge: Homer, when you forgive someone, you can't throw it back at them like that.
- WWF: After the The Rock vs Mankind "I Quit" match, Mankind resented for years the fact that the Rock didn't check in on him after the match. He even used it to start a Face–Heel Turn against Rock years later. Meanwhile, Rock thought he had checked in on Mankind, and was quite apologetic about it when finally told.
Hello, Unknown Troper. You'll need to get known to lend a hand here.