When you fly an Asian or quality Middle Eastern airline, you expect that lavatories will stay relatively clean throughout the flight. I’ve seen ANA flight attendants cleaning restrooms between passengers, and Emirates has even had staff on its A380s dedicated to this cleaning.
After a long haul flight on a U.S. airline, though, it’s almost de rigueur to expect that by the end of the trip lavatories look like something out of a post-apocalyptic zombie film where we everyone must band together to rebuild humanity out of the ashes.