Even the Dalai Lama gets angry. The trick is what you do with it.
What did the Buddha teach about anger, specifically righteous anger? Is any anger acceptable in Buddhism?
The Dalai Lama recently answered the question, "Is there a positive form of anger?" by saying that righteous anger is a "defilement" or "afflictive emotion"--a Buddhist term translated from the Sanskrit wordklesha
--that must be eliminated if one seeks to achieve nirvana. He added that although anger might have some positive effects in terms of survival or moral outrage, he did not accept anger of any kind as a virtuous emotion nor aggression as constructive behavior.
Buddhism in general teaches that anger is a destructive emotion and that there is no good example of it. The Buddha taught that three basic kleshas are at the root of samsara (bondage, illusion) and the vicious cycle of rebirth. These are greed, hatred, and delusion--also translatable as attachment, anger, and ignorance. They bring us confusion and misery rather than peace, happiness, and fulfillment. It is in our own self-interest to purify and transform them.
In the tantric teachings of Vajrayana (Tibetan Buddhism), it is said that all the kleshas or afflictive emotions have their own sacred power, their own particular intelligence, wisdom, and logic. The late Tibetan teacher Chogyam Tryungpa Rinpoche often taught that five kleshas (in the Tibetan tradition, they are greed, hatred, delusion, pride, and jealousy) are in essence five wisdoms. The wisdom side of anger, for example, is discriminating awareness.
How can this be? Anger makes us sharp and quick to criticize, but anger also helps us see what's wrong. Our feelings and emotions are actually serving like intelligence agents, bringing in news from the field of our experience. We should not dismiss, ignore, or repress them.