I’m so glad you wrote. You are right, of course, that learning to control your temper is essential if you are to be successful in relationships or in life. Fortunately, you are only 24 so you are dealing with the issue before you’ve done many things you regret.
I’m concerned that the very thing you’ve done to avoid hurting others and yourself has now become the problem. Staying away from people will not help you learn how to navigate human relationships. Unfortunately, many video games only stoke anger. The adrenaline rush of games that include aggression can become addictive.
My advice? Get out of your room and into life. Stop blaming the exclusion you experienced as a teen for being hostile now. That was then. Now is now.
As teens, we are all kind of trapped in our school and in a particular social group. That’s no longer true when we reach adulthood. There are lots of people who are academically inclined who don’t like or aren’t particularly good at sports. Your task now is to find them.
You may need to see a counselor to help you build some of the very practical skills needed to come to terms with your feelings about the past and to build the anger management skills you need for the future. Here are some tips from the American Psychological Associate to help you get started: http://www.apa.org/topics/anger/control.aspx
But a once a week session with a sympathetic and skilled therapist isn’t going to do it. You also need to start connecting, up close and personal, with real people in real time. That means joining something where you will meet like minded people. Start or join a chess club or get involved in politics or find a charity that you can feel passionate about or learn to ballroom dance. It doesn’t matter what you do. Just do something you care about that attracts other people who care about it too.
Some of those people will inevitably say or do things you don’t like. Good. That will give you practice in dealing with issues and not throwing away perfectly promising relationships just because of some conflict. Working through conflict, not blowing up, is what makes for lasting and strong relationships.
I wish you well.