There was a great anecdote (or perhaps an urban legend). Back when Mir space station was still operational, one of its crews lost something. What it was exactly

There was a great anecdote (or perhaps an urban legend). Back when Mir space station was still operational, one of its crews lost something. What it was exactly doesn't matter, but they looked everywhere. Twice, and then some. Out of utter desperation and puzzled beyond belief they started peeling off parts of the cabin walls and looking underneath. And what do you know - under one panel there was a folded piece of paper that said "It is not here. We already looked." Signed by another crew from a year ago. Apparently they also lost something, but were thoughtful enough to leave a note. So, yeah, notes are great... even if not terribly useful :)