Content Warning: This section of the guide includes discussion of mental illness, addiction, graphic violence, and death.

Harris explores the complexities of changing ingrained behaviors. The chapter begins by challenging common misconceptions about habit formation, particularly the popular but unfounded claim that people can establish new habits in a specific number of days (such as 21 or 28). Harris explains that habit modification requires months or years of consistent practice, as the brain creates new neural pathways rather than erasing existing ones.

Harris presents a systematic five-step approach to habit modification. The first step involves identifying triggers—the situations, thoughts, or emotions that precede unwanted behaviors. The second step requires examining both the benefits and drawbacks of current behavioral patterns. The third step focuses on developing alternative behaviors aligned with personal values. The fourth step anticipates psychological obstacles that might arise during change attempts. The fifth step explores available support systems and resources.

To illustrate these concepts, Harris uses procrastination as a central example. He demonstrates how this common behavior pattern can be analyzed through his framework, examining its triggers (such as task-related anxiety), benefits (temporary relief), and costs (not completing important work). Harris emphasizes two key strategies for successful habit modification: starting with small, manageable changes and maintaining supportive self-talk.