Have a look at the following Videos showcasing How Ideas get killed during Focus groups.
I remember reading somewhere about Henry Ford saying that if I had asked people they would have said that we need faster horse. Similar would have been the case with Walkman, Ipod and other products. Thats where Design Reserach (to capture insights on what customer wants) & Validation tools come in handy and the overall notion of distinctive value (whether the new idea/product/service will be able to provide differentiated value to customers which is not being met by any other product/service as of now)
Have a look at the Videos.