I think that one really important thing to note when you go to Japan is the fact that there are near to no public trashcans anywhere. Of course, there are trashcans in convenience stores and sometimes in train stations, but when you are walking down the streets of Tokyo, finding a place for your trash can be difficult.
When I first went to Japan, I was completely unprepared for this. Why on earth would Japan, one of the top models of efficiency, have no public trash cans for those just walking about the city? It honestly was not that big of a deal, but for an American who is used to disposing of her trash anytime anywhere, at the time, I thought it a bit troublesome to have to carry my trash until my return to the hotel. So why is a place with basically no public trash cans still so clean? Well, like most urban cities, there are people who clean the streets of Tokyo, but is there some other underlying factor to this unnatural cleanliness?
Yes, yes there is. Japanese people themselves tend to be more likely to keep the trash with them and wait until they get home, pass through a train station, or pass by a convenience store to throw their trash. This idea that public spaces should be kept clean is part of the Japanese culture, and that is why it works to maintain the cleanliness of the busy cities, despite the number of people living there.
If you are a foreigner in Japan, I would not get annoyed that there are no trash cans. Just carry a plastic bag in your backpack and put your trash in there! It is a very small aspect of Japanese society, but at the same time, a very important one to keep in mind from a foreigner’s perspective. Even at home, people in Japan must sort their garbage very carefully, so just be mindful of where you end up throwing your wrappers and bottles.