Underlying any effective user-centred designer is the fundamental desire to be of service.
Understanding derived from empathy drives truly insightful requirements gathering. What is it really like for the user? How do they feel? What do they want? What are they afraid of?
An non-overtly "expert" attitude keeps the designer's ego in check; engender a more congenial and less prescriptive demeanour essential for successful charrettes. More "what if you exploited this option..." and less "just do this."
A desire to deliver transparent solutions; because they work so well the users are hardly conscious of them. Unlike some other design professions, user-centred design is less about look at me and what I have designed. But rather more about look at how people are so much better off.
