If you keep it all to yourself always I think you will damage yourself and those close to you. But in letting it out I think it pays to pick your forum. Anger is best dealt with in the long term by being examined and thought about and dealt with, but there are many places where that can't happen. Having a best friend or counsellor can help do the work. So can private writing. Venting immediate anger in company where your anger may hit others' triggers is almost always a bad idea.

Another of my friends on LJ has set up a counselling filter so they can talk about private feelings in friendly and non-judgemental company - would that help you?