Harry Brignull quotes a passage from Susan Marks' Finding Betty Crocker to tell the story of how the cake mix maker used a clever bit of imagination about the process of using their product to give customers the feeling of playing a desirable role--that of home-maker and cook. They did this by simply requiring that real eggs be used in making cakes, rather than incorporating powered egg, and marketed this as a benefit.
Brignull sums up the use of psychology in the creation of this story and sense of role as a clever manipulation of the user experience.
[P]sychologists realized the customer wanted to play the role of a successful home-maker and cook. We could even go so far to argue that their customers may have felt societal pressures to perform this role well. The egg, therefore, becomes more than an ingredient, and more than just an extra pleasurable step. It becomes a prop, enabling the customer to play a social role.
Brignull points out that we can make that comparison to usability and efficiency vs. the creation of emotional contact and the feeling of satisfaction. The egg stands in place of some role that enables some aspect of the fulfilling experience. Looking at the experience from this perspective has so much to do with understanding the customer, and what they want to get out of making cakes.