Do not expose sole!
Do not point at people or things with your feet in Thailand. This is considered very rude, as the feet are considered as the most inferior parts of the human body. And do not sit on the floor of a Temple with your feet pointing at the Buddha Image!
Showing someone the sole of your feet is also taboo in the Arab world. The foot is considered a dirty part of the body, showing your foot to an Arab person is a sign of disrespect to the person. Also showing a foot to someone, could be taken as turning your back to someone.
In America, do not casually take off your shoes or bare feet in front of others, which give people the impression of barbaric debauchery, as only in the bedroom, or between lover to take off their shoes. So do not take off your shoes when visit an American house.