Smokers!
I started renting a nice large (15x30) storage unit a couple years ago. It even has electric! Great place to keep my bikes as well as work on them.
All that changed when a group of older guys rented the one next to mine for the purpose of re-selling stuff to the public though FBMP ads.
It used to be a peaceful space for me to "get away" and indulge in my motorcycle therapy.
But the worse part is this one guy who is there more often than the others and always has a fag in his mouth. You know how cig smoke is....you just can't escape it when someone is puffing nearby......