It's also evident to me from my occasional urge to strangle the idiots who park supermarket trollies in such a way that they block aisles in front of me, or who take what seems like an unreasonable amount of time to operate the pay-and-display machines in car parks when I'm queueing behind them.
I apologise for these reactions. I'm aware that it's happening. It's symptomatic of something wider and deeper, I suspect. I'm attempting to address the situation, mostly by distancing myself from situations which prompt this sort of attitude until I can get my personality on a generally more even keel. You can see an example of this in action if you click on the fifth link, above.