People filled with self-contempt project their feelings onto others and then become angry with the person holding their projection. In other words, they assume others judge them as harshly as they judge themselves and this makes them furious. They do not realize that the judgments that anger them are coming from within. They may retaliate and act out in aggressive ways, never knowing that they are reacting to their own version of reality.
If you suffer from chronic anger, look within. Letting go of bitterness, resentment, and harsh self-judgments will improve all of your relationships. It may just save your life.