Toilet training is clearly not equal in the many parts of my world. And new information can change the flushing habits of people brought up push the chrome handle after doing their business.
I work in a 7-story museum and library. My co-workers average more than two college degrees each. The bathrooms in our building are shining clean. But in the 4th floor men's room, walking up to a urinal means looking down into yellow water. At 9am the water is blue from the previous night's cleaning. But the 4th floor has offices for the most environmentally conscious members of our staff. Which means, I suppose, "If it's yellow, let it mellow, if it's brown, flush it down."
At home, my 12 and 13-year-old sons are still being trained to aim, flush, and wash. They always get two out of three. I occasionally listen for the proper sequence of water sounds and correct on the spot if there is a mistake. But sometimes when I take a shower I find and unflushed toilet.
In Iraq the toilets were often horrendous. Once people were posting Facebook pictures of a turd that would not flush and got named Il Duce, after Benito Mussolini. How the connection was made, I don't know. These guys not only pissed on the seat, they shit on it which seemed to me physically impossible. But who knows. On drill weekends, many soldiers clearly do not know urinals flush. Or maybe they are environmentalists.
In any case, most days, I see yellow water somewhere.