Rehab and Other Gab

I went to our mailbox today to post a letter that I wanted the mailman to pick up when he delivered today’s mail.  When I checked the box, however, the mail had already come.  Drat!  So I picked up today’s mail and drove to the post office to mail my letter.  When I got there, the letter had disappeared!  What?  I searched the car fruitlessly, so I drove back to the mailbox to see if I had