What kind of bad driving annoys you the most?

Is there any particular driving behavior that especially irritates you as a driver, passenger or pedestrian?

As a driver it irritates the hell out of me when people run lights and about hit me, and when people either signal and don't turn or don't signal and suddenly turn. Warn people where you're going you morons!

Slow drivers in the fast lane, drivers making turns without signaling, cell phone drivers........

When my grandmother was still driving, she used to stop halfway through an intersection if the traffic light turned yellow, then back up! Needless to say, I've been driving her everywhere for the last 10-12 years now. . .

Bullshitting in the passing lane, acting like you're going to turn then decide against it at the last minute, driving slow as hell when I'm trying to get somewhere, constant breaking for no apparent reason, not knowing how to merge, not knowing how to parallel park (which I should let slide because most people in this country do know how to either), etc, etc.

Oh jeez:

The aforementioned Left Lane Dicks, not knowing how to merge into traffic and not using turn signals.
Waiting until the last possible moment to pull out in front of me (when there's no one behind me for a half mile and they can't wait an extra two seconds) and then stopping 50 ft up the road to make a left turn.
Riding my ass when I'm doing the speed limit in the right lane.
Riding my ass when I'm doing the speed limit in the right lane with their brights on.
People who can't stay in their own lane because they're afraid of the concrete barrier.
People who sit there letting everyone merge.
People who are overly-cautious.
People who are overly aggressive.
People who try to sneak in at the head of a line of traffic.
People who don't clear the snow off their car.
People who take up two parking spaces or who can't park in the middle of a parking stall.

Hyacinth Girl wrote:When my grandmother was still driving, she used to stop halfway through an intersection if the traffic light turned yellow, then back up! Needless to say, I've been driving her everywhere for the last 10-12 years now. . .

My grandmother was terrifying!!! she drove right over a concrete bumper, didnt think anything of it and kept going!

but to answer the question.. people who cut me off... dont just jump in front of me. I can speed past them if they get out of my way... so stay out of my freakin way! I swear to you.. i will have two reactions if i ever get hit.. it will either be throw myself out of the car as if i were dead and sue their asses.. or beat the shit out of them... depends how bad my car gets chewed up