It clouds our vision, cuts us off from the object of our fury, and drives us to do things which we may later regret. It makes us a source of worry to others. Anger makes us think we feel strong, but it is a sign to others of our true weakness. When it is chronic, it shows how little power we have, or how out of touch with our power we are. Anger arises from frustration.
Frustration arises from attachment to an impression of how things ought to be.
Sometimes anger is appropriate. Sometimes it is dangerous. It is always a luxury which we spend at the expense of our spiritual well being. Emotions come to us unbidden. Sometimes they stay longer than they should.