I would have to agree with @michiiella here. I don't think closure is necessary but if we were good friends before and formed a great bond, then it may be necessary. I don't think I'll be able to live knowing my ex/friend is mad at me. Some people need an explanation and some people just don't (flings, maybe). I never had the courage to talk to any of my ex boyfriends right after we broke up, usually because I lost affections for them already and I was too much of a coward to give them the real reason. For my previous relationships, though, both of us did not need any form of closure because we weren't friends, but our relationship just sprung from hook-ups that lasted longer than they should. But I've learned from them and now that I want a guy whom I am great friends with, and I'm thinking closure is definitely necessary. It can either save the friendship, or not.