People who want to sell something tend to set the price far above what others think it’s worth. That’s human nature, but it isn’t just greed. The sheer fact that we own something affects our judgement as to its worth. PsyBlog details six reasons buyers and sellers (or owners and non-owners) don’t see eye-to-eye, and how some use these psychological quirks to increase business. http://www.spring.org.uk/2008/04/6-quirks-of-ownership-how-possessions.php
The theory is that if one searches hard and long enough, you will constantly find buyers who are willing to pay more.
But eventually, there has to be a cut off point!