What causes anger?

I think anger mostly stems from this inability to do anything to correct a situation which causes distress and this may be anything from oppressive parents or an oppressive spouse on whom you are financially dependant .It Could be anything or anyone from whom you feel you have no choice to get away from...That helplessness when compounded from repeat occurance of the same distress gets bottled up in anger and if this anger is not unbottled in a conscious manner by assessing and acknowledging the actual cause of distress, it might end up causing a change in personality pattern.
I have seen quite a few people who are abused by their parents who end being the same worthless parent that caused them such distress.I have see this relative of mine..All her life , she was treated like dirt at her home by her mother and now she is a parent and she herself ends up behaving the same nasty way with her own daughter.Hmmmm.I would think she would actually make an effort to be different..but i think sometimes people are like that...Prolly this is the only chance in life she is getting to talk down to someone or to control someone else's life...and she is knocking herself out...the hapless child..hmmm