In Keith Robinson’s article on User Experience and Expectation, he references the piano stairs experiment to illustrate how a product can exceed users’ expectations by developing an emotional connection with a design:
"This is a great example to think about! The design of the stairs, while not technically better than that of the escalator, drew 66% more people once it was designed to be fun. I think the implications of that are amazing. Meeting expectations is a great baseline, but to do something great you’ll want to go beyond that."