I should clarify a bit here; I have been a collector/dealer of all sorts of vintage collectibles for over 40 years. In that time dealing with people, I've heard every line in the book that people use to get a better price. Is it annoying to have someone tell you they really want it for their collection, or their dying uncle who had it as a kid, only to see them flip it immediately for a fat profit? Of course! But it's how it is in our capitalist society, it's how it is (as so many have said above) so sellers don't be naive. My attitude for years now is once I sell something, I don't care what someone does with it... they can sell it for a big profit, or run it over with their truck, I don't really care - if I got my price for it, that's all that matters. If I sold it too cheaply, or fell for their BS, that's on me; they won't get the chance to do it a second time though.
I'd venture to say 99% of us would like to buy something at the lowest price possible, and when we sell something we want to get the highest price we can... that's simply human nature, especially in our system of trade. My problem here really is those who try to leverage a seller to negotiate a better price after the fact, especially when the thing was a bargain to begin with... THAT'S what I find despicable. I offered this buyer a remedy; a full return/refund but he still tried guilting me, and essentially threatening my reputation if I didn't give him a discount. It happens on ebay too, buyers leveraging a rebate or refund, but there at least you have an advocate (in both ebay and Paypal) to settle baseless complaints designed solely to lower the price, or threats of affecting reputation (leaving negative feedback). Here, this buyer is inferring he'll tell others in this community that I'm dishonest, it's obscene really, and sad he's willing to stoop to that just to get a couple of bucks back. It goes far beyond BS-ing me to get the best price out of the gate, it's downright malicious, and abhorrent, and lacks the honor I usually see here on the CABE.