Smokers. I have to walk home from school every day inhaling smoke from idiots who can't wait until they're off public property to have their daily dose of lung cancer.
Luckily my school has smoke alarms in the bathroom so less people do it. However some people know how to not set it off.
My old schools bathroom was a damned gas chamber, you couldn't see it was so smoked filled. By the time I finished pissing I would smell like I just got out of a burning building filled with tobacco.
Couples.
Not just cutie kissy couples, but couples in general who walk incredibly slow.
AND TAKE UP THE ENTIRE HALLWAY AND MOVE IN YOUR WAY WHEN YOU TRY TO PASS.
RRRRRRRRRRRRRRRRRRRRR.
Thats when you pull them apart, I had to do that to a hand holding couple who were taking up the open spot so I walked between them, may have been a richardhead move but damn.. they need to move over.