Originally Posted by WChou

I'll toss one in. I was travelling in China with my grandmother in the the early 90s. Air travel and its amenities were still new to many first time flyers. Midway through a flight on a Soviet-era Yakolev YAK-42, I went to the lavatory to discover its occupant did not know there was a door lock. A toilet seat was also a cultural oddity as I found him standing on top of the toilet. I quickly closed the door and returned to my seat. About 15 minutes later, I went off again to the lavatory. In almost a repeat incident, I opened to door to find someone standing on top of the toilet.

I cut my losses and decided to wait out the flight. Upon landing, we were simply pulled off the runway, walked down a set of airstairs, and were directed toward a set of metal barricades demarking the end of the airport. Without sanitary facilities in sight, I elected to "wash down" a taxiway sign at the edge of the runway.