As always, it's about asking the right questions. Asking a customer what they want, and you'll come to the conclusion that they don't know what they want.

Customers know what they want to do. In your Henry Ford example, they know that they want to get from point A to point B faster.

Customers don't know the right way of implementing it. That's why they hired you to implement it for them. They don't know that there are better alternatives to "a faster horse" out there, or better alternatives to an access-based exchange-and-IIS-powered monster out there.

In the end, you have to find the right questions to ask to find out what the customer wants -- this takes skill, and it takes digging, and extracting the essence of their responses. It's part of your job to find out when a customer is telling you what they want, and when they tell you what they think they want, but are really describing the way they think something should be implemented.

Figuring out the difference is the hard part.