Anybody can become angry - that is easy, but to be angry with the right person and to the right degree and at the right time and for the right purpose, and in the right way - that is not within everybody's power and is not easy.
Anger and aggression sometimes seem to be protective because they bring energy to bear on a particular situation, but what needs to be acknowledged is that that energy is blind. It takes a calm mind to be able to consider things from different angles and points of view.
Anger and fear undermine our immune system, while warmheartedness brings peace of mind. Therefore, just as we teach children to comply with physical hygiene for the good of their health, we should also counsel them in a kind of hygiene of the emotions.