All great design is effective, but not all effective design is great.

You’re more likely to achieve great design if you work harder and longer. A great graphic designer keeps moving little things around on the page, even after a lesser graphic designer would say «the design is done.» The same is true for interaction design.

The beauty of interaction design versus graphic design is that you can keep testing your work on new people, and improving it over time.

At a certain point the graphic designer ships. Web and interaction designers never really ship; we’re always somewhere in the middle of a process, learning from the people who interact with what we make.

Jeffrey Zeldman.