Once you're finished with a relationship, it's easy to slip into the "I hate you" mode (love and hate are very close to each other, and sometimes the other person truly deserves your hatred) or the "they made a mistake letting me go" attitude. And, sometimes you just pine after them, missing the "what could've been" you imagined in your head.
I've taken a different approach, trying to not let this person live inside my head rent-free. It's not that I'm not a good man, it's more I wasn't good for them (I'm assuming). I don't wish them ill, I don't wish them well; I try not to think about them at all. It's not easy (nor is seeing them 5 days a week), but I think that ultimately it's the healthiest. At least for me it is; for others, your experience may vary.
Oh, and if your friends and family hate/pity this person, that's perfectly fine. Nothing wrong with having people in your corner feeling the things you're trying not to feel LOL