Cultural custom

I think it is strange that people in America or other countries don't take off the shoes in their house.
In Japan when we enter the house, we always take off the shoes.
I think it is very natural.
If we don't take off the shoes, we got a carpet or flooring dirty.
I don't want sit down on such a dirty carpet or flooring!!
I think most of people in Japan don't like it.
So I often wonder why people there don't take off their shoes.
And I think it is very strange..