I can't represent all my clients equally if I have to waste time stroking some amateur's ego. It isn't worth my time. I've got other clients, who act as professionals should, and they are much more enjoyable to represent. I don't need the stress of unprofessional behavior. One final myth exists that I would like to clarify.
Most agents earn ten to fifteen percent of an author's royalties.
Unless they have an author like Clancy, Azimov, Grisham, Christy, etc., they are not going to make much money for the time they spend. Let's look at the math. Take a new author, never before published. If the agent is good, after months of working on submissions, telephone calls, and selling, they may sell it to a good publisher. The publisher's first run will probably be only 5,000 to 10,000.