Last time I went to the post office, I sealed my box with duct tape and apparently that’s a no-no. The lady at the counter ripped off my duct tape and used the free priority mail tape on my non-priority mail package.
Yesterday, all I had at home was duct tape, so I used it. When I got to the post office, I covered it with priority mail tape. Got in line, handed in the package, and the very same lady said I couldn’t use that tape - it’s for priority mail only.
So I ripped it off, exposed my illegal duct tape, cheerfully handed the box to the post office manager, stole the priority mail tape as punishment, and walked out.