I was feeling ill while shopping one day and ran for the bathroom. I was wondering why there were so many "sinks" on the wall and only one stall. It wasn't until I finished clearing my colon that I finally had the mental clarity to realize I had wandered into the men's room and those were urinals, not sinks. Fortunately there was no one else in the bathroom at the time.

I make sure to triple-check the signs now, LOL