LOL! Cogito No. The ones I have trouble with are the ones who refuse to help themselves. It looks a lot like you do the research - and some of us are your research sources, which is fine - and actually learn with each machine. I get frustrated with the ones who just want cheap machines from me then want me to tell them how to fix them.
Worse still is the people who want my serviced fully rehabilitated machines for $25. My time is worth more than if I worked at McDonalds. What I chose to give freely - ie the QB or a blog I'm not allowed to mention - is my choice. Someone who tells me in so many words that my time isn't worth anything? Completely different.
One that comes to mind is a friend of a friend who keeps buying parts through our mutual friend and is making up names for things, wants to know how to fix things and won't even provide a photo of the machine - this is a Singer, but one of the ones I don't get a lot of info fro the serial number, i.e. is not in the ISMACs comprehensive list. My friend just says why don't you take the machine to her and the reply? "But then she'll charge me to do the work!" He sighs and says "But it will work when she's done and you can just sew!" I sigh and wonder if I've "helped" myself out of work.
There's nothing wrong with negotiating for a better price. If you can support it with good reasoning, I may even meet you part way. I've "offered" on several machines over the years and in probably 90% of the cases have gotten a little off as a result. I go in knowing the value of the machine both in the market and to me and exchange my "discount" for information if they want it - i.e they have another machine they're trying to sell, they sew and have trouble with their machine, etc.
In most cases, the "offers" I get are via email before they arrive to see the machine and usually half or less of the asking price. Those are insulting. They'll never get the machine at that point. I'd rather bury it in the backyard. People who show up to try one of my machines typically leave paying asking because I can justify my prices. When they see that I'm selling a machine usually for less than the price of a service and it looks and sounds and sew like it does... they usually hand over the cash and thank me.
I guess that's the other part of it. If a person is too lazy to even come to see a machine before low balling me AND says my time isn't worth anything... that's when I start boiling and the smoke detector goes off.