1) People who have quick cars (eg, Camaro SS), but don't take care of them or just don't know anything about it. You ask something like, "What gears you got in the rear?" ---"I dunno". These are the people who can't change their own oil.
2) People who immediately assume I drive an average of 85 mph on the hwy just b/c my car is a Mustang with a 351W 5.8 L. Dude I got a 3-speed auto with 3.55s in the back. Even if I had a 5-speed manual with 2.73s, why I gotta be flyin down the hwy at terminal velocity?
Think b4 you babble. (happens too often to me)
3) A person who really believes that all American cars are inferior to imports b/c this person had a broke down Dodge Omni when he/she was 20 years old and it didn't last over 200,000 miles.
4) Cool muscle/sports cars with SNOBBY owners.
a) Guys with cool cars that act stupid after they get beat (by an old '79 stang),
5) Idiots on the local cruise strip/lot that do STUPID CRAP and mess it up for everybody. (eg, everybody's chillin in the lot, a little revving, maybe some horns going off, then this moron in the jacked up Toyota with flowmasters wants attention so he does a burn out and throws beer bottles on the lot.
6) Many of the above already written in this thread....