Japan
Don’t tip anyone: “Tipping is just not part of the culture. Don’t even leave the small change. People will come running after you with it.”
Don’t wear your shoes in someone’s house: “If you see other people taking their shoes off, do the same. (Note: there’s a small area right inside the entrance called a ‘genkan’ which is usually one level below the rest of the house, where you take off your shoes. You don’t take them off outside the house!)”