Marc Hassenzahl's Why, What, and How.

While reading Marc Hassenzahl’s chapter on User Experience and Experience Design (link below) in conjunction with Buxton’s “Sketching User Experiences”, the differences and what user experience is became clear to me. Commentaries by several user experience gurus at the bottom of Hassenzahl’s chapter are also helpful in understanding user experience and experience design.

The Philips’ Wake-Up Light is a perfect example that describes a (what Hassenzahl calls it) surrogate experience. Let’s say an enlarged version of the wake-up light that was flat and mounted on to one of the bedroom walls, it would only be visible and active during the user set time—by doing so, would it enhance the user experience?

The three levels of Why, What, and How that Hassenzahl, lays out are easy to understand in terms of the experience of a product. Basically, Why clarifies the “needs and emotions involved in an activity, the meaning, the experience.” After the Why is determined, then the What “determines functionality that is able to provide the experience.” And the How is “way of putting the functionality to action.”
Ref: http://www.interaction-design.org/encyclopedia/user_experience_and_experience_design.html