Chewing with your mouth open and smacking. My fiance does this and drives me INSANE.
Not cleaning up after yourself. I have random odd's and end's laying everywhere, but I'm talking about food and dishes and stuff. This is my fiance's other bad habit, and he is quickly going to be broken of it.
Anyone who is not from Japan who uses words like "kawaii" and inserts random Japanese words into their language. For God's sake, you are NOT Japanese! Don't act like it! It looks so stupid. If you want to speak some Japanese, then learn the language and actually speak it, rather than looking like a complete dingus by inserting random words here and there. It's stupid.
Over-protective parents. Again, fiance's mom. She has to know everything he does every day, and she has to call him, every single day. If we're in the basement, where his bedroom it, either watching a movie or on the computer, she will stand there at the top of the stairs just watching us. If he asks her if she needs anything, she continues to just stand there and stare at us. If he gets up and says over and over, "" Mom, do you need anything? "" She STILL just stares at us and just walks away after awhile. It is creepy beyond belief.