We don't value our floors over friends, as some one will say.
We value our homes, our lifestyles, and we want to share that with others.
I found this on a comment thread on Apartment Therapy.
This blog recommends that you adopt a shoes-off policy in your home, not just for family but also for guests and other visitors. Socks, slippers and bare feet are fine indoors, but not shoes. Just say NO to shoes in your house!