I once heard an amazing psychological Dharmic explanation of an angry person and I will try to recall the explanation here. An angry person is a person who has developed a habitual pattern of not taken responsibility of one's life. The irresponsibility can be manifested in a variety of ways and is willfully repeated over and over again till it becomes deeply ingrained. Alternatively, the person could go through a habitual pattern of escape and never really facing his/her problems.
This obviously would have karmic repercussions including losing friends, inability to complete tasks and work, losing integrity and ultimately a loss of self-esteem. This loss of self-esteem becomes deeper and deeper as the vicious cycle of irresponsibility develops. Irresponsibility will inadvertently lead towards deep-seated anger. Once it reaches this stage, the person becomes like a loose cannon, unable to control his or her anger. There is no immediate solution to anger at this stage. The only way is to control it is with knowledge, self-restraint, vigilance, doing lots of contemplation, Dharma work, Sadhana, soliciting wisdom Dharma Protector like Dorje Shugden and most important of all, taking responsibility and hence, taking charge of one's life back.