Not seeing the dirt....
Oh, I know....my grandmother of blessed memory and now my mother would be horrified to know they missed a spot, but they did, and do, which is why my self-appointed job is to quietly re-clean it the minute they step out of the room...
That's why when I used to clean for older folks, it was harder, because they were around, and because they're like, "but I already cleaned that!", and it's important to spare their feelings....God knows, most of their kids don't care...
Come to think of it, a real estate appraiser must see a lot of interesting "props", especially because they frequently belong to those who an everyday person wouldn't associate with the scene...