Actually scaredy you just made my point even better as the car dealer is a great example. You can now go online and see what the seller paid for the house, you can find out the loan amounts, you can see what else is for sale and what things have sold. You can get an idea of how much they are making on the sale, then you can determine a fair margin, tell them to take the offer or you will go buy the house down the street and then they can laugh at you.

You have alot more knowledge now which has helped buyers but it helps sellers too as they have better knowledge of what demand is like also. Homes are unique assets and the price is determined by a willing/able buyer and seller just as if you were selling a piece of artwork. An appraisal is just an opinion of value like an agent/seller set price. Appraisals are far from the end all and be all.