10. Failing to introduce people. (It’s always awkward if you don’t introduce two people when you’re their only shared acquaintance.)

9. Not excusing yourself to take a cell phone call. (This is especially aggravating at the dinner table.)

8. Arguing over a dinner check.

7. Being late.

6. Not giving up your seat to someone who needs it more.

5. Treating service staff poorly.

4. Always talking about yourself.

3. Being a slob at the gym (sweating on equipment, hogging machines)

2. Grooming in public. (Yes, we’re talking to you ear cleaner, nail clipper, tooth flosser. Save it for the bathroom.)

1. Eating with your mouth open.

Source: AskMen.com