One of the best chapters in Steven Levitt's best selling book Freakonomics involves the issue of Realtors being bad negotiators because their economic incentives are based on a quick transaction which puts the buyer or seller in a bad negotiating position.  The book outlines how real estate agents use their market knowledge against their clients in order to gain an advantage and earn commissions.  In his study of over 100,000 home sales, he found real estate agents get more money and take longer to sell their own homes versus the homes of their clients.  Selective stories of multiple offers, spooking mentions of other buyers looking at the home are great motivators for buyers to write full price offers when they may not need to. 

This story from the book (page 72) about John Donohue, a law professor at Stanford, sums up why you should never completely trust a real estate agent, even your friend.

"I was just about to buy a house on the Stanford campus, and the seller's agent kept telling me what a good deal I was getting because the market was about to zoom.  As soon as I signed the purchase contract, he asked me if I would need an agent to sell my previous Stanford house.  I told him that I would probably try without an agent and he replied, 'John, that might work under normal market conditions, but with the market tanking now, you really need the help of a broker.'"  Within five mintues, the zooming market had tanked.  Such are the marvels that can be conjured by an agent in search of the next deal.

Bottom line: You better do your own homework or you may be in danger of losing tens of thousands of dollars.  It is because of this reason, CataList agents are paid with a base salary and bonus to avoid the commission-driven negotiating position that gets many consumers in trouble.