Edward, I don't think it's a good idea to be scaring yourself. Especially many times when we do this it has absolutely no bearing on actual reality. We all have our fears and concerns, but lately, I have been trying to substitute fear with faith. When I say faith, I mean that everything will work out fine if I do my part to make it happen.
My biggest fear at my age is, maybe, the inability to care for myself when I really get old.
I think you can conquer the temper thing; I had to do it myself when I was younger. I finally came to the conclusion that it's just not worth it to put myself in a position of rage and hot-headedness. These days I just listen to what someone says and let them be right, even if they're not. I don't have to be right all the time (even if I am).