Anger has a function, of mobilizing our resources, when we are unsuccessful with calmer responses. It can give us energy, minimize our regard for risks, minimize our regard for other considerations, such as appropriateness, or right and wrong. It can also just seem to do that, because we may falsly believe that calmer responses would not have been effective. Anger allows us to respond quickly, without the interference of thinking. In other words, it may not be the best of our options, because we did not take time to think.
Anger serves as an anesthetic for other feelings.
If we feel fear, humiliation, guilt, lonliness, grief, rejection, or some other feeling which is more painful than anger, anger will cover it up. It also creates the illusion that we can do something about it. If we are ashamed of those feelings, it conceals them from others, and creates a public image of greater strength, or so we may believe. Anger allows us to blame others for our feelings. By assigning blame to others, we attempt to remove bad feelings from ourselves, by assigning responsibility for their being there to some one else, at least in our own minds, and hopefully in the minds of others.