Designing a good feeling

After years of focusing on functionality and usability, the designers of interactive systems seem to be developing an interest in the role of user affect, a general term they use to indicate the feelings, emotions and moods that working with computer programs and computermediated information is associated with. They begin to acknowledge that usable design is not necessarily pleasurable or desirable. But what must designers do to address feelings, rather than design for task effectiveness and efficiency? How to design product features with predictable emotional responses?