How can I radically change myself?

I'm getting tired of being myself. I'm just an angry violent person with no ambition or direction in life. I look at the kind of person I am and ask myself "would I be this person's friend?" and the answer is always no. I try to be nice to others, but it doesn't change how I look at myself. When it comes down to it, nobody knows me better than I do. Does anybody have any suggestions?