Anger is a voice inside of you saying "I think what is going on here is unfair".
Anger is one of the most taboo of all feelings. Showing a hint of Anger usually results in someone being judged as bad or dangerous.
Perceiving a circumstance as being unfair to ourselves or the people and things that we care about creates Anger. This feeling is meant to drive us to reconcile and make fair again. When used in a positive way, Anger is a very powerful motivator for change and justice.