In most cases, I'm a forgive and forget kind of guy, unless the person does the wrong stuff over and over again despite being told plenty of times that stuff like that bothers me. Usually when that happens and it's clear the person isn't learning anything from what they're doing wrong, I just try to break away and avoid those kinds of people. You can't make friends out of everyone, but the best choice is to at least keep the peace between those people you just can't work with. And if that means just leaving them alone, that's probably for the best.