I've put a lot of thought into this, mainly during my latest commute home. I took a bit of a different approach looking at cars but really owners since it's the owners that make the cars unbearable... My top 10, in specific order:
10. The Tesla owner who became a car-expert overnight. I'm actually a fan of Teslas to some degree but I know many owners who all of a sudden want to educate me on the bajillion reasons Teslas are the best cars on the road and why everything else is now inferior.
9. The $30k millionaire.
8. The "supercar" owner who thinks they're better than the rest of the population because they drive a supercar. Bonus points if your supercar isn't a supercar, like the guy in a C6 Z06 told me his car is "just as special as a Ferrari or McLaren, only 1/2 the price"...inaccurate on so many levels.
7. People who think they're car people but aren't car people. Let me explain... The guy who owns a Lexus RCF, parks next to me, and says something like "Oh man, the new RCF is one of the top performance cars out there right now"...or the guy who owns a Ghibili and tells me "It's the best performance car for the money".
6. "Muscle Car" owners who think these things are high-performance vehicles. I don't have anything against the cars themselves, but your base Challenger isn't a supercar. It tends to be these folks who decide to rev at me when stopped at a light or try to chase me on the highway.
5. Most Uber drivers. Especially in the cities...pulling over without signaling, making a left hand turn from the right lane and cutting off traffic. Doesn't stop me from using them though
4. Fuckboi drivers. You know who you are. Weaving in and out of traffic without using turn signals, cutting people off, etc.. I don't care if you're "going the speed limit"...I've seen too many close calls and it's totally unnecessary. No one is impressed by your ability to cut across traffic in your 2010 3-series or debadged A4.
3. Any type of tuner that thinks their car is way better than it is. I don't mind tuner culture, I even respect it, but your Honda is still a Honda no matter how many stickers you put on it.
2. BRZ/FRS owners that think their cars are the holy grail. The only time I ever got into an altercation on the road was with a FRS owner who was trying to show-off (had a chick in the car) by attempting to race me (in a busy city) with his window rolled down telling me "I bet I can outdrive you". I yelled a few very douchey choice words back...pretty sure I also fit the BMW a-hole stereotype here (was in a white M4 at the time).
1. Really anyone on a cell-phone or not paying attention. Bonus points to the chick with a Starbucks in one hand and cellphone in the other and zero on the wheel. It sounds cliche but your lack of attention isn't worth damaging someone else's car or worse, sending someone to the hospital (or morgue).
***Bonus Round*** anyone with an insufferable vanity plate. I like tasteful vanity plates, but something like 2Fast4U on a C250 realllllly tests my self control.