Absolutely. Maybe you already do this, but when you're pissed, take a day to figure out why. Somewhere in that time, ask someone you trust whether or not they think you're over-reacting (use those words... otherwise, they'll just say what they think you want to hear). Just knowing that I have that tendency, along with a guilty virdict from a buddy helps tremendously to diffuse whatever anger I'm feeling.
Now, if you are justified (or if you don't buy your friend's reasoning), it's essential to your mental health to confront the offender. The most effective way to do this is to be vulnerable. You're probably pissed because you're hurt or you feel used or blah blah blah. Say that (and not "I 'aint no K-mart, so quit asking me for paperclips, bitch!"). Worst case scenario: you feel embarassed for making a big deal out of it. Not a tragedy, but you could always come back and say: "I was sensitive because my grandma just broke her hip," or "...multiple hemorrhoids." They'll understand.
Hopefully you found something useful in that ramble-fest. Keep being laid-back and awesome. That way, if you do loose your cool, you'll be forgiven.