It is your duty to give them what they really want, not what they say they want. It is however, better to propose it to them and get them to agree that your proposal is what they really want before you begin, but they may not have the vision to do this. Your confidence in your own ideas about this should vary. You must guard against both arrogance and false modesty in terms of knowing what the customer really wants. Programmers are trained to design and create. Market researchers are trained to figure out what people want. These two kinds of people, or two modes of thought in the same person, working harmoniously together give the best chance of formulating the correct vision.