First, a disclaimer: I'm not angry. But I have a friend who's in a crappy situation right now, and that made me think of how I've handled similar situations in the past.
In my sophomore year of college, I punched a door. I was in a frustrating situation and I felt helpless to resolve it. Sometimes you just need to do something stupid to release all that frustration/irritation/anger, and in my case I chose to punch a metal door. Of course, I didn't realize at the time that the door was metal, and the third knuckle of the middle finger of my right hand is now about 1.5 times as big as the one on my left hand as a result of that particular little outburst.
That was the last time I chose to punch something in frustration. I found a better way of coping: full body self-abuse in the form of a ridiculously intense training session.
Whenever I'm mad -- shallow breathing, clenched fists, tunnel vision MAD -- I head to the gym. I channel the anger and the frustration into my workout. Anger makes heavy squats go up faster, and adds a nice edge to that light-headed feeling of accomplishment after a particularly challenging deadlift.
No matter how the workout goes -- whether I crush the weights I was going for or fall short on every single exercise, I always feel better after I've lifted. I've gotten the raw emotion out of the way at least a bit and can think more clearly about the problem that caused my distress in the first place.
Besides, it's impossible to feel angry when all you're focused on is trying to make sure your rubbery legs don't give out on you and make you collapse in a heap just outside the gym doors.