I don't have that problem in game. However, I've had to learn how to deal with this in real life. I actually had to go to anger management therapy when I was I the Navy. Honestly, that dude didn't help me at all. He insisted on breathing exercises that only served to piss me off (how's that for ironic).
I have learned over the years to see the humor in all situations, even at my own expense. Learn to laugh at yourself and open yourself up to laughing at others. I am now accused of being a smart*** an awful lot, but I haven't dragged anyone out of their car years
I do occasionally make the comment nowadays, "you're lucky I take that little pill every morning that stops me from strangling the crap out of stupid people".
Really though, look for the humor and laugh at yourself. You'll find if you look at yourself in the right way, you're hilarious! Screw the deep breaths!