maybe there's mud or dog poo or dog wee wee - hey you never know...
What bothers me is when I can see clutter from a person's picture. If it is on the floor and there's nothing around it, fine, if it is on a table and you can see all this junk in the background, drives me nuts and I wouldn't look again.
if the area looks clean, it actually doesn't bother me at all.
If the floor looks dirty that's no worse than the table being dirty to me.
It's about cleanliness for me, no matter where they think they can capture the best photo.