In no specific order:
1.) Overly vulgar or ignorant people.
2.) People who don't know to stop talking, even when everyone in the room is completely ignoring them.
3.) People who try to muscle in on any conversation, even when it's none of their business, and usually add negatively to the discussion.
4.) People who only talk about themselves and will at any opportunity.
5.) People who try to push their beliefs on you.
6.) People who think they, and only they, are right.
7.) People who don't even have an incing of an open mind.
8.) People who wear those oversized sunglasses.
9.) Lairs and criminals.
10.) People who play garbage music out loud in a quiet place like a library even after being asked to turn it off several times.