This is where I get my mail (it's a few houses down from me).
Image Source: Me
If you have a parcel that won't fit in your personal box (left side), they put it in a locker and leave the key for the locker in your private box. Some of you probably use these types of mailboxes. I got an Email from the USPS recently, saying a package had been delivered to my mailbox. However, there was no package. The mail carrier undoubtedly put the key to the locker in the wrong mailbox. Sadly, whoever got my package kept it (f**king, c**k-sucking, mother-f**ker, etc., etc., etc.). Extra sadly, I was expecting the game I ordered at Gen Con - Moonshine Empire. Extra, extra sadly, I'll never find out who the thief was, so I don't even know whose house to burn down. 😡
I gotta do a bit more research as to what the package was, but hopefully I can get reimbursed.