I don't understand how some people turn stupid 37,000ft above ground. I get it if some don't know what vacant and occupied means, but how can you not see color? They know to queue at public toilets when  it's red/occupied, but onboard they become stupid, or blind.
When you see a knob, you turn it. When it's a handle, you pull it down. When people get stupid, they stare at the handle like it's some alien device.
I can't remember seeing any toilets without a flush handle or button, so why do some think it's auto flush in the aircraft? Imagine opening the door to a toilet bowl half filled with what looks like stale beer.
Everyone locks the door when they enter the loo, but some are obviously exhibitionists, many have gotten off to me opening the door then quicky shutting it in shock. Locks are not toilet ornaments.
Toilet seats are called that because you sit on it, not climb on and squat. If you do not want to come in contact with the toilet seat at all, at least do the hovering thing. 
Do not attempt to take a dump in turbulent weather, for I do not want to clean crap off the wall, again. How it got there I can only imagine.
The door with the tiny window and big handles, that is not the toilet door with a picture of clouds and blue sky. That is the aircraft door. The doors that looks too small for a kid to enter, those are compartments. Do not laugh as I have seen with my own eyes, some dimwits trying to open it only to give up and say "toilet" when asked if I can be of any assistance.
And today I am talking only about aircraft lavatories, imagine these people on a whole journey.