Quoted from TimeBandit:

There is a pervasive pathological behaviour amongst a whole bunch of said people to simply "win" at the transaction. I personally start in the middle and if I get dimed I give a bit. But I usually only get moved a tiny amount as I start at the right price. As a result, the average time it takes me to buy or sell a pinball machine, or anything for that matter is about a day and everyone moves on happy. There are posts here where someone admits they walked away from their grail pin three years ago over the inability to adjust by $100. WTF is that all about. The desire to be not moved off their price is so high that it is actually the highest priority of the transaction. But that is not going to change. They are just like that. It's like pedants. They can't help it. Like I say, it's pathological. I think you have to simply know your market, and be the guy who yields a bit. I find that over time the result is you pretty much always get what you want. And you won't be keeping score anyway, cause you don't care that much about "winning" everytime you interact with another human being.