While a display of anger might serve as a form of communication at times, anger itself is a reaction due to loss of control and points to a lack of self-discipline.
Stress related anger outbursts are a sort of mini-breakdowns, in which the pressure is released outwards in a violent manner. When the stress becomes prolonged the angry person might find that after the outburst of anger he or she feels temporarily better, and tries to invoke a reaction of anger in similar situations.
In the long term, the person who assumes an attitude of anger engages in self-delusion: places blame on others and sees anger as a just feeling. Even when no stress is present such a person will try to get angry because it can give a temporary feeling of release and satisfaction.
A person who turns to anger gives up self-responsibility and self-control, and deals with stress by violently changing his or her view of the world and oneself. This creates a discrepancy which is severely damaging to the angry person's identity, and leads to a great number of immediate and delayed problems.
Choosing anger as a way to deal with stress is like curing a headache by smashing your head with a hammer.