Kathy Sierra of Creating Passionate Users has a great new post where she illustrates how great product design makes it easy for the user to do the right thing and difficult for them to do the wrong thing.
Simple principle, but difficult to always practice. For example, we know we have some usability issues on the Resurrection web site. We need to make some improvements to make it really great for users, but we can’t do it all immediately. Is the first step admitting you have a problem?