_cf said: Polite isn't the word, it's unthinkable to enter a traditional japanese house with your shoes on.
it's even more unthinkable in a tatami room, not accounting how much tatami even costs and how it's even a big deal when renting/buying a house to know the number of tatamis in a room.
Asian people take shoes in the house incredibly seriously, and it's not just the Japanese.
Here in Finland, when I mentioned somebody that abroad people walk with their shoes on inside, they were like "Doesn't that get lots of dirt inside?". Vicious cycle: 1. Because Door is dirty, wear shoes inside 2. Because I wear shoes inside, floor gets dirty 3. go to 1.