House Shoes

In Korea everyone has a pair of house shoes and a pair of outdoor shoes. Every kid pretty much has the same pair of the "$2.99 special" dark blue rubber Addidas slippers.
When they come in the morning, they change their shoes and then enter the building. If they go out for recess, they change their shoes both leaving and coming back indoors.

It's the same in a Korean house, or traditional Korean restaurant. Everyone leaves their shoes at the front door. Like always wearing clean underwear in case you're in a car accident, you never want to be caught in Korea with nasty dirty socks.