Dan Russell recently wrote about the tendency of developers to design user interfaces that are intuitive to them but not to users. He then counsels:
As interface designers we often achieve our greatest successes when the interface disappears, and getting to that point is what makes us professionals at this game – our willingness to go beyond our personal intuitions and see what really works for our target audience. Great user interfaces are ultimately about creating something that’s ego-less, something that works well for people who are not you and not just the same as you.One of the reasons it's important to keep user interface designs out of product requirements specifications is that you lose the ability to judge whether the interfaces are actually usable. The metrics you use to judge usability - not the designs - are the requirements.