People who wait for the last second to get in the turn lane, then don't even fully get in so you can't get around them.

People who slow WAY down to turn, then start by turning the opposite way a bit, like they are driving a damn 18 wheeler or something.

Truck drivers that want to chat everytime I back out of their truck after loading a pallet on. Then I have to stop, turn of the forklift or scream what!!! EVERY DAMN PALLET.... c'mon dude, we can chat when I'm done. Eventually I tell them to go wait in the truck.