A UX designer’s work should always be derived from people’s problems and aim at finding a pleasurable, seductive, inspiring solution. The results of that work should always be measurable through metrics describing user behaviour. UX designers use knowledge and methods that originate from psychology, anthropology, sociology, computer science, graphic design, industrial design and cognitive science.
When you’re designing an experience, you are in fact planning a change in the behaviour of your target group. You’ve found out their problem and you’re trying to destroy the burden using design methods. User experience lies at the crossroads of art and science and requires both extremely acute analytical thinking and creativity.
User experience design at its heart is an optimisation: an iteratively improved solution to a general problem. UX is the air successful startups breathe.