Anger pollutes the whole body and has very harmful effects on the body afterward. It takes long time for the body to recover. Anger damages subtle energy channels. It is said when one practises regularly, one develops or opens certain energy channels in one's body, especially in the brain. Anger closes or damages these subtle channels.
Anger blinds the mind.
Anger renders clear, rational thinking impossible, and blinds the mind. It takes a long time and great effort to recover to a peaceful, cheerful and clear mind afterwards. Anger damages relationships with others. Anger makes one lose control and perhaps commit actions one could later regret. Emotional damage is very hard to forget in a short time.