Ha!
I check my feet too, and unfortunately, most of the time they are filthy. LOL! I stay outside a great deal. My husband just shakes his head and says You’re a mess, and I say.. I know! I am also a heathen.
After the fact though, I politely remind him who cleans floors and such in our household and he pipes down.
As far as our floors, I am hyper sensitive to my floors mainly because I have felines.
I usually vacuum everyday, and mop at least twice a week. I love my critters, but I am not having a bunch of cat hair everywhere.
I am sure the inside/outside patterns of their dogs alone track quite a bit of dirt inside.