Alcoholics have many unsatisfactory experiences in life. During the initial stages of abstinence, you may come across situations that make you frustrated and resentful. You have accumulated so much anger that it only requires the slightest provocation to set you off. The second reason is that you have found that anger works and that you are conditioned to continue its use. Thus, for you anger becomes a pattern of behaviour.
Anger is expressed by acts of violence - verbal or physical.
Or it keeps simmering below the surface. It burns as a silent resentment. Sarcasm and abrasive humour are also expressions of this bitterness. It corrodes you until nothing is left but a raw-edged hole. Sometimes, suicide might seem as the only way out.