Here's a sketch I drew of me angrily knocking on an airplane restroom door. About 15 passengers were waiting for the two stalls on our flight to California. Only one of the lines for the restroom was moving. The door to one stall didn't budge after 10 minutes. When my husband first knocked there was no answer. I got up there and knocked so loudly I'm pretty sure the people in first class could hear me. It turns out there was some dude in there. When he finally he hauled his ass out the door I was in the other restroom. I could hear him chewing out my husband and the other passengers, though. Apparently he was saying stuff like it didn't matter how long he took because the restrooms are first come, first served. I am fairly certain that if I had been there when he came out of the restroom, air marshalls would have been waiting for one of us when our flight landed.