You’ve probably never used toilet slippers in your regular toilet, but in Japan, they’re a really big deal.
See, when you go into a Japanese household, you have to take your shoes off, because they like their houses clean and don’t want you bringing outside dirt inside. You even have to do this in some hotels and restaurants in the country.
When you use the bathroom, you need to remove your house slippers and put on toilet slippers, specifically for the bathroom. Not only do you have to wear different shoes in the bathroom, you can’t leave the bathroom with those slippers under any circumstances.
It would actually be considered shocking and taboo to do that! You’ll always know which slippers are toilet slippers too, since they’re generally five sizes too small and have the word “toilet” written on them in big letters.