Why do Japanese sit on the floor?

Question:

Answer:

In western houses, floor are like part of ground.
People need shoes, chairs, carpet, beds...... in houses.

In asian culture, floor are like part of extended bed.
Floors are raised and cushioned, insulated. People take off shoes entering houses. They sit on the floor, they even sleep on the floor.
In fact,Japanese kanji character which means "floor" is "床", pronounced TOKO or YUKA. This same character "床" could also means "bed".

It's my personal theory, but the essential part of western houses are roof and wall, whereas that of asian houses are roof and floor.
Most of western traditional houses have very robust roof and wall, but floor is like ground, cold and hard. Most of asian traditional houses have secure roof and raised floor, but walls are sometime very simple and airy. I guess it's because of climate. The mainstream origin of western culture came from north Europe, where they have severe winter. The mainstream origin of Asian culture came from the central or south Asia, where they have hot and humid summer.

Please also remember that many of modern Japanese houses are now very westernized.