RETURN RECEIPT REQUESTED
It's a small thing, but it's like a chigger. You know? Chiggers. They burrow under your skin¹ and itch and burn and when you were a kid you scratched 'em til they bled 'cause they just drove you NUTS.
"Return Receipt Requested" is the chigger of the s.b.'s online world.
"Hi there! I don't trust you! My name is John. I'd like to talk to you about this item of interest to us both, but I don't trust you to behave like an adult human being and reply if you are interested. And oh yes, if you don't reply, I'm going to badger you about it, and if, once I finally reach you, you try to tell me you didn't see my email, I'll triumphantly crow, 'But I've got proof that you opened it on July 19, 2007!' Have I mentioned that I think you're a lying slob? But let's do business. Better yet, let me ask this favor of you, you cheating, lying (until-proven-otherwise) scum. Thanks so much!"
Please, don't anybody say, "Someone needs to get a life." We are busy scratching.
¹UPDATE: Okay, they don't burrow under the skin. From Wikipedia: "Contrary to popular belief, the larvae do not burrow deep into the skin and live there. Rather, the larvae pierce the skin and inject powerful enzymes that digest cellular contents, which become liquified and are consumed by the larvae."
We feel much better.