The reason you put the lid down is because it's there. If they didn't want you to put it down, they wouldn't have included one with the toilet. Besides, what are you going to sit on to clip your toenails?

Apparently, great ranger minds think alike. Not to mention that if I don't put the lid down, the cat tries to drink out of the toilet and usually ends up falling in. And where else would one trim one's toenails?

As for the TP, Gnu is so absolutely right.