Being a web designer is like being the only skilled laborer on a remote island under U.S. law. Not only are you expected to know how to design and build the house, you have to know plumbing, landscaping, painting, electrical wirining, irrigation, obtain the land, the permits, manage the money, secure the loans, and market and sell the thing.
Your client will be the equivalent of New Guinea royalty, somehow important but with a limited budget, may have never lived in a house or had electricity, and will still have the audacity to tell you how they think you should do it. You will be expected to know their culture, language, and what they want-even though they don't.
Oh, and that blueprint you drew up: It will change drastically throughout the project.