Sellers want to hear about how great their cars are, how much the buyer loves them, how much the buyer will love the car when he buys it, etc, etc. Unfortunately, you can't script a sale.
Buyers want a fair deal (or better) for a great car. There will always be disjointed interests because it's a negotiated sale.
You can't set rules for this type of thing. I agree it can be uncomfortable, but compromise is never easy.
