Anger is a natural human emotion. “Is my anger working for me?” is a question you can ask yourself. When anger is mild and infrequent, is expressed assertively (directly to the problem person, in a non-accusatory manner) and without aggression, and the individual is able to “let it go” quickly, then anger may serve the role of simply highlighting your annoyance and it can lead to problem resolution.
However, if your anger is moderate to intense, experienced frequently, endures to the point where you are holding a grudge and are planning to get even, and is expressed in aggressive verbal and physical actions, then there is cause for alarm. You are likely at risk for the negative relationship, health and sometimes legal repercussions related to inappropriate anger expression. Professional help is indicated. 
A by-product of an unacceptably angry person is low self-esteem and often shame.
Anger management programs work to address managing anger as well as building self confidence. Recently There have been six large-scale analyses of adult anger management programs that show this! If you, a loved one or colleague has a serious anger problem and wishes to gain control over the emotion, I invite you to search out a program locally or via video skype (I have all venues available with face to face individual and group sessions in Wantagh, Long Island). Contact l me for a 15 minute phone consult: www.balanceandpower.com
I am Certified Anger Management Specialist by NAMA (National Anger Management Association).
Eileen Lichtenstein’s Balance and Power Blog 