It honestly annoys the crap out of me. I expect more from that sort of employee base.
This is interesting: One official study found that men's rooms might seem to have more trash (paper towels, etc.), but women's rooms have the higher levels of bad bacteria.
We're told to never ever put our purses on the floor either. There's even a cool little portable hook device you can buy if your door doesn't have one (wherever you're at), to hang your purse on.