We have a famous proverb in Japan. "立つ鳥跡を濁さず” It means that the waterfowl take off with the waterside clean, so "let's leave the place where we spent a certain period of time and the place where we stopped by in a clean and tidy state." This is what we Japanese have learned since we were children. （Unfortunately some people forget it..) I think that is one of the good teachings for us to be a good person and for everyone to spend comfortably. so If you travel to Japan, please keep clean of every place you stayed and if you see Japanese people who don't, please tell them this proverb.