The big stuff I'm usually pretty decent managing. It's the small stuff that makes everyday life aggravating.
The one that makes me want to kill someone is people following too close in the store and, for some reason, even if you zig-zag to try to get rid of them, they're still on your heels (as if you're a magnet!). I mean, either back up or go around - but stay out of people's invisible space bubbles!! (I'm still seething from two morons I couldn't shake on my trip to the grocery store Thursday! 
So, my thing is to either manage the big stuff/worries or else put it out of your mind; and take advantage of the small stuff as a way to let off steam, vent, and generally be the miserable, angry, person you need to be once in awhile.
I guess it's because I have kids, and mothers have to "be strong" and "set the positive mood" when the big stuff is going on. A person has to just be angry, small-minded, immature, and miserable once in awhile. 