I read an interesting comment somewhere on the internet from a Polish person living in New York.
She complained that while back in Poland people always take their shoes off and the host may offer to let guests keep them on (an offer normally declined by the guest), in New York the situation was very different. Every time she visited a friend she would be asked to take her shoes off when she would have removed them anyway. She found it really annoying being asked to take her shoes off when she that was her normal custom.
Let me apologise in advance to any Polish people if this happens to you in my house. If you are Polish, I know from experience that you will take your shoes off without being asked, but just in case I do ask you, please be understanding.
Dear Poles, you must understand that we British and Americans are less socially advanced. People in the West have to be trained to remove their shoes. That is why some of us ask for guests to remove their shoes. But maybe if you people keep coming to our country and settling here that might change and we shall all be well mannered enough to always remove our shoes.