Shoe etiquette

In most parts of the world (Asia, Eastern Europe, parts of the Middle East and Africa, much of Northern Europe and Canada, as well as Alaska) it is customary to remove shoes when entering a house. 

In some areas of the United States, especially the Midwest, it is expected that visitors remove their shoes unless a host specifically invites them to leave their shoes on. People do this to avoid bringing dirt, mud or snow into the house. For some societies, including those in Asia, indoor footwear may be provided for guests.

In the Middle East, parts of Africa, Korea and Thailand, it is considered rude to show the soles of the feet to others (even accidentally, such as by crossing the legs). 

Shoe throwing is a great insult in some areas in the Middle East and in India, according to Jamal Elias, an Islamic Studies professor from the University of Pennsylvania. In addition, in Thailand, it is an extreme insult for the foot, socks, or shoes to touch someone's head or be placed over it. Although feet touching heads is an extremely rare occurrence in any society, some Muay Thai boxers insult each other by "kicking" the opponent's head with their foot (most Muay Thai kicks are executed with the shin).