Great Designs Should Be Experienced and Not Seen
http://www.uie.com/articles/experiencedesign/

Spool, Jared M.
User Interface Engineering
2009

Abstract:

When things are going well in a design, we don't pay attention to them. We only pay attention to things that bother us. The same is true with online designs. We attend to things that aren't working far more than we attend to things that are. When the online experience frustrates us, we pay attention to its details, often because we're trying to figure out some way to outsmart it.