A good builder sees customer education as part of the process. If the customer comes along with unworkable ideas in his head and refuses to be educated, a good builder politely declines the sale. Many builders also decline sales of bikes that are outside their area of expertise--for instance some specialize in track bikes, and decline to build MTBs and so on.

For some real insight into custom framebuilders, their customers and how everything works, spend some quality time at Velocipede Salon. It's a forum like this one, only founded by framebuilders for framebuilders and their customers.

In particular, I recommend the "Smoked Out" section. Each thread is about one builder only. They introduce themselves, tell about their background, and then it's all Q&A from there. If you can read only two, I recommend the threads from Strong Frames, where Bob Ross got his bike, and Kirk Frameworks.

If you have a plastic cover to keep the drool off your keyboard, also look at Friday Night Lights, where builders post photos of this week's work, and the VSalon Cycling Gallery, where customers post pics of their bikes.

EDIT: And don't forget to introduce yourself in "Welcome, Say hi".