Mouth noises.
I hate, hate, hate when people chew with their mouths open (this includes gum), talk with food in their mouths (this includes gum), or make mouth- smacking noises. I also really hate kissy noises in the movies.

Gum.
I hate gum. See #1 for more details.

Spitting.
Ew. Ew. EW. Also, smokers? I used to smoke, so I'll consider myself educated enoguh on the subject to saw this: if you need to spit when you smoke, STOP SMOKING.