Customs and traditions vary with time and place. It indicates how people do things as a group. It is an indication of oneness and unity. There are certain rules acceptable in your country but not in Japan. Take heed of these things during your stay in the country.
There are so many rules in Japan and the train is not immune from this. If you happen to ride a train, make sure to talk softly. This is an obvious rule for the Japanese people. You might think many Japanese cannot speak English but it doesn’t mean they don’t understand English. Be careful in talking about private matters too loudly even if you are using your own vernacular. It would be uncomfortable for people around you to listen to your stories.
Added to this, don’t blast your music too loudly when you are listening to it, even if you are using a headphone. They even have a sign for this.
Do you know the reason why Japan is so strict when it comes to sorting trash? It boils down to the fact that the country is a small island nation and they cannot afford to have huge tracts of land to serve as landfills. This is an important way of life for the Japanese. Everyone is expected to follow the rules, including foreign people. When you sort trash properly, it also reflects your personality.
Every place has a different way of doing it. You have to accustom yourself first to avoid further mistakes.
Never bring inside the restaurant any drinks which you’ve bought outside. This is considered rude in Japan as it shows you are not enjoying their food and drinks inside. Some places will even tell you to put them away.