Some call it, "nesting".
Some call it, "paranoid".
Some call it, "unnecessary" and "silly", but for me, it is not even a question.
Some people only toilet paper the seat when at a rest stop or a port-a-potty so they don't understand why I do it all the time, even at work or in a restaurant, "Don't you know they clean it??" Um, yes. I do, (although the standard of "clean" is sometimes questionable depending on where you are...), I just have a problem putting my butt where someone else just had theirs.
I guess I'm just weird like that.