In thai culture, sock and underwear are different from other kinds of clothes. Because sock are worn on the feet and underwear is worn on the private of the body, they considered to be dirty, and people who wash clothes for a living often refuse to wash them. However , to foreigers , sock and underwear are pieces of clothing, just like shirts and pants. When they send out their clothes to be washed, they may send socks and underwear at the same time, and expect them to be washed at the same time.