In most of my experiences, I usually end up upsetting the seller in one or two ways. I only shop for John Deere round fenders, and in most cases, the sellers don't have the experience to know what year tractor they are selling, so they list it as a 1963 110 "Rare".
One time I called a guy who had such a tractor listed for sale and I asked to come and see it. The seller proceeds to give me some type of unknowledged, off the internet, fly by the seat of his pants history lesson about the tractor. I play stupid and don't let on that I'm a collector or have any experience about these old round fenders. Anyway, we meet, and I can quickly tell that the tractor is a 1967 110. I listen to his story again about how this tractor is the first year of production, only year of production with the fiberglass hood, and it's extremely rare as there were only 1000 of these made. He proceeds to tell me that he knows he can get a lot more for it than his asking price, but since I came to look at it, and I'm the first one to inquire about it, he'll let me have a deal of $500.00. I look the tractor over as if I'm interested, and then after a few minutes, I tell him what the tractor really is, and then give him my phone number and my counter offer. I got a really strange look of surprise at first, then a look of anger, as he just figured out that I played him. Upset #1
After I looked at the tractor, told him what I know, and he called me virtually everything but Troy, I left. Nothing gained, nothing lost. However, that same seller called me after three months of my visit, and told me he will sell me the tractor if my offer still stands. I told him the offer stands, and I'd be over that weekend. Turns out, my offer was better than everyone else's that came to look at the tractor, and he quickly found out, that I wasn't wrong with the knowledge that I expressed to him that day, as he was told the same thing from others. My offer was a little higher than what the tractor was worth, but I had to sweeten the pot if I wanted a call back from him. He didn't get what he wanted for the tractor, and he didn't have what he thought he did. Upset #2
I don't have a problem with people who want to buy low and sell high, and if money can made on a deal, than that's great, go for it. My problem with over priced items is this. If you are going to try and sell something for an incredible amount of money, then do some research on the item, and find out all that you can about it. Don't make something up, blow smoke up someone's butt, and hope that you convinced them to make the deal. At least know what you are selling, get an idea as to how long the item was manufactured, and do some research to find out what the going market rate is for it. Don't make yourself look more stupid than your high asking price.