"I find it odd that not one person has mentioned the most wonderful side effect of anger: catharsis."

That's like saying - No one has mentioned that gambling is really exciting when you win.

Anger is not always cathartic. It often gets people into a bigger mess than they were in to start with, with greater pressures to deal with as a result.

So the "buzz" is catharsis.

A fairly compelling argument in support of the view that expresssing ones anger in order to enjoy catharsis may well be an addictive practice.

Addiction = "Habitual psychological and physiological dependence on a substance or PRACTICE beyond one's voluntary control."

Stress is a definite physiological concern. If you find yourself relying more and more on stoking up your anger so that you can get that all consuming and liberating catharsis as a way of dealing with stress then that would constitute an physiologically addictive practice.