6. The Dictator. The dictator refuses to listen to anything constructive you have to say. He's already got his mind made up, and he'd rather disregard your expertise than deign to compromise his initial vision. Anything you try to suggest becomes an argument, and he's not willing to listen to reason. Overall, you end up losing productivity or quality on almost every job.
To better manage this client, set firm yet reasonable expectations at the beginning of the relationship. Establish yourself as the authority, and listen to his advice, but stand firm if what he says goes against your better judgment.