I think you missed one. We have an anonymous electronic suggestion box at work. This showed up a couple years ago:

Everytime I go into the mens bathroom and pull up to the urinals, I can see that the "Riddler" has been there again. I mean the millions of follicular question marks scattered and strewn about the lip of the urinal. I mean, do people yank out a handful of dna and sprinkle them about everytime before going? I went to college. I've seen gross stuff before. But, this is just disturbing as I can't picture anyone yanking out a handful. Maybe more frequent cleanings throughout the day? Ultimately, in a perfect world, you'd just ask people to not decorate, but this isn't a perfect world.

Since-hairly yours,

Anon

Now, as for the boogers on the walls, I've noticed that's an international thing. I've seen it in Canada, I've seen it in the US, I've seen it in India. What possesses people to do this?

Oh, and then why is it that people say "hey, what's up?" by way of greeting you in, entering, or leaving the bathroom? What sort of answer are they expecting? "Oh, you know, just doing a little number two. How 'bout you?" Or maybe "I just needed a bit of private time to dig a couple gems out from my nose -- my cubemate is kinda cute, so I couldn't do it in front of her. If you want to check them out, I left them on the wall in the third stall."