I have one that's new to me... and not really a horror story. I received the trade-in box for my watch today. Someone apparently thought it had something "interesting" in it rather than just being an empty box. So they opened it up. And then used the little included piece of tape to tape it back up again. I was laughing as I called Apple Support, because I'd have loved to have seen the face of the would-be thief when it was just an empty box. The box isn't damaged at all, so support said to go ahead and use it with my own tape.
I have other horror stories for UPS, FedEx, and USPS, but they're not Apple related. Hopefully this makes a few other fellow-sufferers smile.