Lean startup and the product manager

In this video, Alex shows you an operational view of lean startup and how to use it to avoid waste and keep your team focused as a product manager. He presents Fogg’s Behavior Model of Usability v. Motivation. Are there products you have used in your experience that are difficult to use (low usability) but worth the reward (high motivation)? Have you experienced simple processes that were not worth your time? How do you see product management creating a resource in between?