1. ... Ellipse. I know I overuse this one, but...damnit, I like it.
  2. , Comma. I love the comma, but I'm aware that I'm not 100% certain how to use it in proper sentence structure, and, crap, I'm sure I overuse it.
  3. - Dash. I'd be willing to bet that I misuse this one at least 90% of the time I use it. The fact that I use it - at all - probably constitutes overuse.
  4. ! Exclamation Mark. It's so exciting though!! I probably overuse this one, too!!!