Anger is a major issue.For me anger can be defined as the non acceptance of things which are beyond our control.If you accept it it is called tolerance.
Keeping anger bottled inside us is not good either. It's a natural emotional feeling. It can be destructive or constructive depending on where and how you channel it.
What about anger directed at yourself (self-hatred), when you are indeed in control of what may happen, but refuse to act because of fear, lack of courage, etc.?