Anger in the short run is seen as reasonable because the person is basically saying, “What you did was wrong. I am a person worthy of respect and that is what I am asking of you.” At the same time, if this anger stays with a person, deepens, and lasts for many months, it can be counter-productive. One then might demand too much from the other. One might turn the quest for justice into a motivation to seek revenge and hurt the other. So, we have to be careful when discussing the benefits of anger. There are such benefits in the short-run, but anger has a way of taking up residence in the human heart if we are not careful and thus the one harboring the anger can be damaged.
Learn more at Why Forgive?