Women that do their makeup while driving. And they're in the turn lane, waiting to turn in to K-Mart which is at least 10 car lengths away from the light, and there's nobody else in that lane. Then you put your blinker on and begin to pass them, when they step on the gas to keep you from getting in the turn lane. So you miss your turn and have to waste the gas to go to the next light that also turns towards your destination, but it's one of those "Left turn YIELD on green" lights. So you wait. And wait. And nudge forward a little so you can ACTUALLY make the turn. And the light turns yellow and the oncoming traffic STILL DOESN'T STOP so you're screwed no matter what you do.
Then you get to your big name store and you're about to pull into a spot when the joker in the adjacent spot decides now is a good time to pull through and nearly hits your car as it's still getting into the spot. And the joker in that other car looks mad at you for inconveniencing him.
Other drivers in general.