From Hackers and Painters, Paul Graham (Design and research, p.216–217):
Design begins by asking, who is this for and what do they need from it? A good architect, for example, does nor begin by creating a design he imposes on the users, but by studying the intended users and figuring our what they need.
Notice I said 'what they need', not 'what they want.' I don't mean to give the impression that working as a designer means working as a sort of a short order cook, making whatever the client tells you to. This varies from field to field in the arts, but I don't think there us any fields in which the best work is done by the people who just make exactly what the customers tell them to.
The customer is always right in the sense that the measure of good design is how well it works for the user. If you make a novel that bores everyone, or a chair that's horribly uncomfortable to sit it, then you've done a bad job, period. It's no defense to say that the novel of chair is deigned according to the most advanced theoretical principles.
Any yet, making what works for the user doesn't mean simply making what the user tells you to. Users don't know what all the choices are, and are often mistaken about what they really want. It's like being a doctor. You can't treat a patient's symptom. When a patient tells you his symptoms, you have to figure out what's actually wrong with him and treat that.
This focus on the user is a kind of axiom from which most of the practice of good design can be derived, and around which most design issues centre.
