The expression of anger is not the anger. Anger is an emotion much like all the others, it's to inform you how you're feeling about yourself in relation to the world. Something is bothering you!

Get "technical" and figure out how to figure out :-) and express exactly what that something is. Anger is a tool, lets you know when something needs fixing in your life, when one of your boundaries has been crossed or you're confused and things need straightening out. Don't look at the expression, look at the problem and state it.

"I left my car with you this morning, just paid $363.47 for repairs after doing without transportation for 10 hours and nothing has been done on the car." (My response instead was to burst into tears because I was afraid I was going to kill the shop foreman, not helpful :-)

When you have stated the problem, see if the other person agrees with that statement; sometimes we have it all wrong and mixed up! If they start with the excuses or ignorance or agree, you know you have hit the nail :-)

Tell someone what you want done, "I'd like you to fix your mistake immediately" and a time frame/consequence, "I'll be back in an hour/tomorrow morning/with Arnold Schwarzenegger :-)

And if you can't get satisfaction, help solving your problem (your car needs fixing is the problem; don't lose sight of the original problem!), "I want my money back now/am cancelling my check/talking to my credit card company and will be notifying the Better Business Bureau to file a complaint. I will not be bringing my car here for repair ever again and will be telling anyone who asks me about car repairs about my experience with you here today!"

THEN, reflect and figure out what you learned, what you will do differently next time; what you would like in the future! "Gee I wish I knew a good mechanic" might get you looking for one and asking friends who they take their car to and doing more research so you don't have to worry next time you have a problem. You can get to know your mechanic or, decide to become a mechanic/fix your own car, etc.