I could go on all day!!
Tailgaters are my #1 pet peeve... especially when I'm in the middle lane and the left lane is clear.
If I'm in the left lane and someone wants to pass me, if they're polite about it (i.e. they don't get too close, just close enough that it's clear they want to pass) I will move into the next lane and let them pass, but if they hang 2 inches off my back bumper at 80mph flashing their high beams and giving me the finger, they can just forget it.
I hate being stuck behind people who drive really slowly... especially if they speed up as soon as they get to a passing zone so that I can't pass them.
People on cell phones (other than hands-free units). Hang up and drive!!
People who cut you off and then go slow.
People who pull out of parking spots without looking, or change lanes without checking their mirrors and blind spots.
GARBAGE TRUCKS. Garbage truck drivers think that they can ignore all rules of the road and drive wherever they want to, whenever they want to, simply because their vehicle is larger than almost anything else on the road. (Sadly, they're right.
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People who don't stop at stop signs, particularly if there is already a car in the intersection. More than once, I have nearly been creamed by some @$$hole who didn't think "stop" applied to him.
People who don't use turn signals, or who put their turn signals on and then go straight - "Surprise!"
People who don't realize that a right turn on red is legal in most places, and sit there until the light turns green... and people who don't realize that a green arrow means you can go in the direction of the arrow even if the main light is red.