I sometimes visit a friend (Myra) who's OCD about taking off shoes.
She lives in a high-rise building in Boston. With a doorman. This is not a barnyard or dirt road area. It's well paved. Urban. Upscale urban. After crossing the brushy thingy at the entryway, I walk across a carpeted lobby. Then I take an elevator and polish the soles of my shoes further by walking at least fifty feet down the carpeted hallway.
I would guess that at this point, the soles of my shoes are cleaner than the soles of my feet.
In her 4x4 foyer she has a little sign asking her guests to please remove their shoes. There's even a little bench, put in at the request of her mother. Even Mom has to remove her shoes.
Myra's carpet, by the way, is not white, but slate grey.
I love the feeling of the thickly padded dense pile carpet on my bare feet,
and it is her place, so she gets to make the rules, but sheesh! A sign even!
Lindy