FACT: I made just such a joke. I didn't let on that I knew who he was (and tbh I didn't until I was typing in "Daniel Fortson" in the "From" field) because I'm a total pro, but when I handed him his receipt I said "That'll leave here this evening and go on a plane, but not a supersonic one, and be guaranteed for delivery tomorrow morning before 10:30 am local time." He smiled at that and left. True story.