I despise the asshats that think the exit-only lane is their personal express lane, then cut in front just before the exit ramp. They think they're special.
Left-lane lamers are also...lame. Seriously, if you're doing 65 in the left lane, and are being passed on both sides by cars doing 70-75, you need to move over.
The worst is when it's trucks. I never see semi-trailers in the left lanes (semi drivers are, IMO, the best drivers on the road: they keep long following distances and always let you in), but I do see the smaller one-piece trucks (Penske rent-a-truck kinda size).
And people cutting me off just pisses me off. I don't care if you cut me off with 3 carlengths to spare and you're going faster, how do I know you aren't going to cut in front of me and dive on the brakes (it's a type of insurance fraud: the "swoop and squat"). Do you think you're special?
I'm a decent driver. I don't tailgate, I don't cut people off (if I can't avoid it, I give them at least 3 seconds warning with my turn signal), but I do keep up the pace (if the lane is open in front of me, I jump up to 80mph).