Some habits are, to put it nicely, very annoying. While I am guilty of some myself, it's safe to say that the world would be a better place with out them.
Talk to yourself out loud
We all talk out loud every once in a while, at least I do, but please don't mumble to yourself for three hours straight in a silent library.
Constantly interrupt others
Unless you have something really important to say, it can wait a minute or two.
Listen to loud music in quiet setting
Listen to it as loud as you want, just as long as I can't hear it.
Whistle
This is just a pet peeve of mine. People who whistle loudly in a largely silent environment just rub me the wrong way.
Chew gum with your mouth open
And PLEASE do not start popping loud bubbles.
Chew anything with your mouth open
Just making sure that all bases are covered.
Cough profusely
This one is out of your control because trying to hold back a cough is useless. That doesn't stop coughing from being annoying, though.