I'm not crazy. Well, at least I don't think I am. Every once in a while I hear the new mail sound. I usually always have Mail running and I've never heard the new mail sound when it wasn't running (phew - I haven't lost my mind yet). But,when I check Mail there aren't any new messages! In fact, just before posting this thread, I heard it and the last new mail message I had received was over an hour ago. There aren't any unread messages either.
Has anyone had anything similar happen to them?