I have 'sworn' up and down that I have lost a cat....only to find some sleepy eyed boy or girl- still warm from sleep, come up to me, as if to say, "what? what?"
That happens to me all the time. Whenever one of the cats isn't visible I always go nuts and think that they accidentally ran outside. Then I ask my roommate if she let the cat out, then make myself look stupid by asking "are you sure?" Then when I find a sleepy cat under the bed I feel like an idiot.