You probably get very frustrated by the buyer who claims that he or she has to go to a Higher Authority before making a final decision. Unless you realize that this is simply a negotiating tactic that's being used on you, you feel that you'll never get to talk to the real decision-maker.
When I was president of a real estate company in California I used to have salespeople coming in to sell me things all the time: advertising, photocopy machines, computer equipment, and so on. I would always negotiate the very lowest price that I could, using all of these Gambits. Then I would say to them, “This looks fine. I do just have to run it by my board of directors, but I'll get back to you tomorrow with the final okay.”