To Forgive and To Forget, Really... how do you do it? Options

Have you had someone really important and beloved to you do something really bad/dissapointing/whatever to you which you simply cannot forgive, not to mention to forget? When in the end you ended up filled with so much hate, mixed with love and resentment no matter what you've tried to really forget and forgive? And the feeling still there like for 2 years as it kept popping into your head even when you were not intentionally want to think and when you least expected it? Well, maybe I'm in a bad mood today, but really... I want to hear your thoughts and experience on dealing with this.

I can see your point and we all learn what hate is sooner or later.

The only thing I thought was that we don't know if the people that have hurt us ever come to a realization that they are sorry and wish they hadn't done the bad things in their life.

A few people will never come to this realization because there is something wrong with their brains, which in effect, makes them disabled. If we decided to get rid of people who the majority found unforgiveable by say lethal injection, where would we draw the line?