I have pretend conversations in my head with people. I'll scream and yell in my brain at them if I'm upset. Basically, I just say ALL the thoughts that are going on. And then I tend to imagine how they'd respond if I was to do that - and that usually gives me the benefit of having "expressed" the emotions, gotten a response, and know that it's not a good idea. The negative to that: I often feel guilty for things I haven't said! haha.

Aside from that, I take time out for myself and try to do things that are relaxing. It calms me down, with the added benefit of being removed from the people I'm likely to snap at.