I was wondering like googley and I found perna answer enough good for me too. Still sometimes anger could be constructive; if I would be only frustrated by myself or what I can't... I would not be here anymore. Salukigirl, maybe sometimes anger could come from fear but not directly. I avoid for months to talk because I was too angry (fear to unwillingly harm someone with my tone or talking increasing the danger...) I was blocked also to talk .. and maybe for better. I am still angry of fear for others to not have to encounter the same that happened to me. But I am angry because something unfair happened to me and there there is no fear but huge DISGUST!

"If you get angry at a person for treating you badly, really you are probably scared that they don't like you or care about you or are afraid of losing them"
Think of a mother whose cub is in danger because some people's fault; do you think she would be scared -other for cub - or care if the other likes or not. She does not fear losing, not even the cub because she can't think about that!

But too much frustration goes to anger...