Like they said on the Monty Python TV show.... "and now for something completely different".
I've bought and sold a dozen or so airplanes, over a span of 35 years. And a few junk projects that weren't airplanes yet. I have a small amount of business experience, more than some and far far far less than some others on BCP. I have probably spent as much or more time looking for airplanes, reading the advertisements, scanning Trade-a-Plane etc. than most of the people on here.
One of the very worst days in my life was the day I realized that there we have plenty of scum bags, idiots, crooks, drunks, pedophiles, jerks, unrealistic dreamers, well-meaning fools, con men, wannabee posers, and morons in aviation. As a kid I had completely bought into the idea that we in aviation were smarter, better, more honest, etc. than the rest of the unwashed masses. On an overall basis we are, but not nearly by the margin that I had assumed.
Then I started reading Trade-a-Plane: "1946 Piper J-3 Cub, ($3X current market value) invested, you can steal it for only ($2x current market value) !!!!!!!!!" Back in those says a reasonably well restored J-3 was worth about $12-15K and a flying beater was 8-10. If someone is stupid enough to put a fortune into an airplane that exceeds the value of the airplane, that doesn't make it a steal at over-market value.
I had one guy start telling me how much he had invested in a Taylorcraft, and angrily offered to show me the receipts. I told him how much I had invested in the car I sold to buy the plane, and I had the original window sticker for the car, so would he give me credit for what the car had cost me? .
Having read a whole lot of ads, and having gone to see airplanes that were junk when they were advertised as good, I have to say that all of the tricks, lies, BS, and outright misinformation that we normally associate with used car dealers is often alive and well in aviation, even with private airplane sellers.
Went to see a Cessna 175 at El Cajon airport near San Diego several years ago. Several phone conversations with the seller, asking all the questions I could think of, before I went down there. "It's a good airplane, fairly well taken care of..." was the oft-repeated chant from the seller. When I got there, he said he was busy building his RV-6, so just go out to the airplane and look at it all you want, the logbooks are behind the pilot's seat.
Logs showed that a wing had been torn off when tied down in a storm. Any seller with any integrity would have mentioned that on the phone.
Seat track holes badly ovaled, would not have passed the "recent annual !!" by any IA who had any integrity.
15 degrees of play/hysteresis in the control wheel before ailerons engaged.
Considering the geared engine of the 175, and how he said it was "fine, meets all specifications", I left the scene without any further contact with him.
Went to see an Aeronca Defender (pre-war Champ) at Pismo Beach/Oceano CA airport. "Oh yeah, we fly it all the time !! Flies wonderfully ! You'll love it. You'll fall in love with it and fly it home

"
Wings obviously attached hastily, rear wing struts rigged to provide wash-IN instead of wash-out (which directly leads to dangerous stall/spin behavior).
Aileron system turnbuckles barely screwed together, no safety wire, no cable tension
Logbooks missing, despite advertisement claiming it had logs (Oh yeah, I'm pretty sure my brother in law has those, I'll send them to you later")
There are more stories that I have, and I'm sure many people on BCP have plenty of similar stories than I do.
So although the whole "sell with integrity" and "I know what I have, here's the price, go elsewhere if you want to ask a thousand questions" thing may work in some cases, like it or not there are a whole lot of people who are not trustworthy but who use that same high-handed positioning and "take it or leave it" posture to get people to buy a junk airplane.
For me, and for most of us, an airplane purchase represents risking a fairly large sum of money. If it's your money, and someone is telling you "as is, where is, that's enough questions, don't waste my time", then you have every right to be really careful before spending it. Sellers you don't have to put up with BS and nonsense from buyers, but buyers you have the same right to not put up with evasiveness, misinformation, or fear mongering from sellers.
If a buyer gets screwed he's getting every bit as much of his time wasted as the seller is,
but the buyer ALSO is losing hard money.