Different things in our lives are connected to one another. Nutrition is connected to mind-set, which is linked to productivity, which is connected to performance, which, in turn, is tied to fitness, sex and sleep. All these aspects of our existence are connected to one another. Not only are these aspects interlinked, but they also are interdependent. The author, Aubrey Marcus, makes a point about focusing on one day at a time while trying to change or improve something. In other words, the main message of the book is to 'own the day'.