I once had a friend with which I fought almost all the time. We were miserable, the two of us. Eventually, he just dropped me (didn't return my calls, answer my emails, etc). I was very angry, but decided not to do anything about it. Over time, I came to respect his decision and even be grateful for it. I have no idea how he is doing. I tried to send him an email, but he didn't respond ;-) I'm very much happier without him in my life. I owe him a debt I can never repay. I hope he is similarly happy without me in his life.
If there is something that your friends are doing that causes you a problem, you can discuss that very reasonably without being angry. If it's something that really, truly deserves your anger, then it is probably best not to discuss it at all. There is no need to make everyone even worse off than they were before. Letting go of the situation that caused the anger is the first step in healing yourself. Don't bind yourself to it. Sometimes this means losing a friend, but in this case, wouldn't that be a potentially good solution?
