Olson often refers to the idea of compounding interest. In financial spheres, this typically refers to interest that is earned on interest. Olson applies this concept to success, stressing that success accumulates with repeated action over time and emphasizing the idea that Transformation Is Habitual. Compounding interest functions almost as a synonym for the slight edge and reveals the mechanism by which it works: through a small start that builds steadily to a greater sum. This idea is most prominently introduced in the fable about the two boys who have to decide whether to take an immediate lump sum or a single penny that doubles in worth. The idea of compounding returns regularly throughout the book to highlight how little actions can yield greater results.

The day of disgust is the day when a person realizes they are repulsed by the life they are living and gain clarity about the nature of their circumstances. Olson describes his day of disgust early on in the book: “That moment of impact we sometimes hit in our lives when we come smack face to face with our circumstances and, without having a clue to the what or how of it, make a decision to change” (12).