I have a terrible one: I bite my nails.
I wish I could stop, and have for short periods of time, but always revert to picking at them. It's awful but nails, I just can't quit you.
Another bad one? I'm always late. It's terrible and I feel bad for the people who are waiting, which in turn stresses and angers me and I'm the only one to blame! I just cannot be punctual. #truth
Sound off, what habit do you wish you could break?