It's interesting that sometimes think we know what we want, but we really want something else. And in the space between the two is usually where the really great ideas are born. When somebody discovers what we really want instead of continuing to give us what is we think we want. Of course, this is a similar idea to the one discussed in the Innovator's Dilemma, another book on my "must read" list.
... many of the great ideas are not precipitated by the customer. While the customer knows what he wants, he doesn't always know what's possible. And that first dawned on me in my earliest days in business. When I was new at IBM, working in sales and taking a management training program in Sleepy Hollow, New York, I came back to my room grumbling about the lack of speed and reliability of the tape drives, and wondered why the engineers couldn't do something about it. My roommate stared at me with a look of total exasperation. "Boy, you guys in sales are all the same," he said. "You remind me of the farmer in 1850. If you asked him what he wanted, he would say he wanted a horse that was half as big and ate half as many oats and was twice as strong. And there would be no discussion of a tractor."
David Kearns, former CEO of Xerox