Once, I was at a public restroom when this guy in the urinal next to me kept shakin' his business.
I didn't notice for the first 5 seconds, but my subconscious tipped me off.
I went, washed my hands, and walked out the door, where I paused. I wondered if he was doing it with the intention of being offensive, and whether I should go back in and administer a grade A ass-kicking.
The mall was rather empty, no kids around, so I just left.