I know exactly what you mean! DH and I have had some bad luck with rentals and have had to move 3 times in 2 years, and every time the real estate picks up on something, no matter how thoroughly we've cleaned (and I am a real neat freak).
You spend so much time cleaning, and stressing about if it's clean enough, then the real estate comes back wanting you to do (or redo) something. One time we were asked to remove a cobweb from the outside of a window that I'm sure had been made after we'd cleaned! Sometimes I think they just come back with these little things to prove that they've looked through the place.

We are about to move again (into our own house this time, thank goodness), and I am dreading the cleaning (and re-cleaning) we'll have to do.