There are cultures where it's bad to walk into someone's house wearing shoes. There are houses instead where you are supposed to walk with shoes or sandals on or you will get your socks or feet dirty. Shoes or no shoes, that is the question.
You might think it's hard, but it's usually easy to know whether they allow shoes in the house or not. When you walk in, are there shoes near the entrance? Put your shoes there. Otherwise, just come in.
But sometimes, the owner doesn't care and walks everywhere with their shoes on. But you see the floor and it's so nice, so clean, so comfortable. You can't walk on it with your shoes on, can you? Especially knowing that you stepped on mud when you were coming here, and broken glass, and probably the dust of the dry remains of poo. Ew!
No, so you take your shoes off and prepare to dirty your feet for the cause of not disrespecting the beautiful rug. You step on it and you walk, then sit on it. You want to lie on it but you look at the owner's shoes. You know it's dirty. But it's so beautiful.
Can I rest my head on it?
So you lie on the couch and dream of dirty feet and a small dragon that spews fire from its toothy mouth. Pretty world.