A big thing with almost everyone I know is forgiveness. Even after something horrible, despite how much time it takes, almost everyone I know is under the philosophy that you have to "forgive them and move on." Moving on, absolutely. You can't be weighed down by things forever, it'll tear you apart. But you should never EVER be ashamed that you aren't willing to forgive someone. I know this seems like a crazy thing to say, but almost everyone I know is obsessed with the idea that time really does heal all wounds. Apologizing for being a shithead doesn't make you exempt from me hating you, me not wanting you around, etc. Two examples.
A friend of a friend was at a small party of ours, about 25ish people. He got super wasted, and while usually pretty decent while intoxicated, was super into this female friend of ours. So he tried one last time to convince her to leave with him, which she wasn't up for. So he started trying to pull her out of there, playfully at first, and then she clearly looked super uncomfortable. Some people were jokingly like "oh, look how funny he is that he's drunk, hey man, don't do that" and thinking it was some hilarious thing. She gave him a more firm no, he got pissed, and actually shoved her away. She fell over, and he didn't even blink. All he said was "I'm going to get another beer." Fuck that. Another friend and I ejected him from the party in the same manner. I go to slam the door shut, he was trying to reach back in, and his arm and shoulder get smashed in the door. Nothing serious. But he's pissed, so there is a small fight, but he's gone. Next day, a few friends are telling me "Dude, he was just drunk, like, you should apologize and we can get on with it." "No." "No what?" "Why the hell would I apologize? He was a shithead, drunk or not, isn't sorry for what I did, [female friend] doesn't forgive him." "Well she will. You gotta forgive people." No you fucking don't.
Shorter story. My dad cheated on my mom. Because he's a shithead. His mother and two sisters found out I have no intention of inviting him to my wedding and launched a crusade on his behalf. "You have to forgive him, he's your father." Nope, I sure don't.