Every human being that works has to know that what they do matters to another human being.
Purpose is an important driving force and a strong motivator. There are other books that talk about the "Why?". If you don't know why you are doing something, it's easy to get demoralized. Take weight loss for example. It's not just simple to say that you want to lose X lbs. It's important to know and really internalize why you wanna lose weight. In my case, it's to become a better sportsman, and a better father who has energy to play with his kids and participate in their activities.
