One mistake foreigners tend to make in Japan is to forget the slipper rules: In particular that you have to change your shoes before going to the bathroom. This doesn’t only apply to private rooms, but also to hotels and restaurants. In hotels you get given horrible plastic sandals that make you wonder how many people have worn them. If you haven't practised changing shoes, you can suddenly find yourself standing in the living room with your toilet slippers on; a real faux pas, but one that happens quickly because it's such a new choreography. It's even worse when you have a child with you, as I often did. In the hotel, the cleaning ladies notice if you haven't changed your sandals. Not wearing street shoes in private rooms is not only a rule in Asian cultures, but also in many Arab cultures. Many Japanese wear their shoes one size bigger, they know how to change shoes, they do it at breakneck speed. It's really stupid when you go to Japan for the first time and wear lace-up shoes, like I did. You quickly unlearn that habit.