I don't let things get to me in the first place. I'll get irritated and fix whatever's irritating me. If it's a person, I glare at them until they leave. If it's a project of some kind, I just leave it be for a while and come back later.
If something actually angers me, which is rare, it's usually a complete idiot who's been intentionally trying to piss me off. I bottle it up temporarily and put it to use by channeling that emotional energy into something more productive. I get quiet and tell people to leave me alone for a while, then go to work on something, typically campaigns for D&D. Oddly, these campaigns end up being some of my best.