If you only take one piece of advice from me for the rest of your life, let it be this: When making use of a public restroom, lock the door on the stall.
While at work today I found myself in need of a bathroom break, so I made my way to the Men's Room, found a stall (all facilities in my office's restroom include stalls, including urinals), and gave a light push on the door. It swung open, being that it was unlocked. That's when I found the guy inside making use of the facilities.
"Oh, excuse me," I said as I swung the door closed again. I moved down to the next stall, dumbfounded. "That's the reason those doors lock, ya know," I said to the stall's occupant.
Why would someone not lock the door if he planned to take care of business? I would assume the guy wanted privacy, and I sure as hell didn't want to see certain deeds. Lock the friggin' door!
Whoever the guy was, he quickly flushed and fled the room before I exited my own stall, leaving me to wash my eyes in silence.