I can't keep any open spaces here at home, either. My husband is ALWAYS sitting stuff down wherever he finds an empty spot. In fact, we've got a running joke about it. Whenever he's working on something and loses one of his tools (which is quite often), I shrug and tell him it's on the "nearest flat surface". I'm usually right!
(Drives me crazy, but I love him to bits, so whadda ya do? he he)