Mel Robbins opens Chapter 9 by stating bluntly that life isn't fair, and that the habit of obsessing over others' luck, looks, and achievements is a self-imposed obstacle. She lists numerous unfair circumstances people face and argues that mindless social media scrolling and comparison drain motivation, fueling procrastination, self-criticism, and a self-fulfilling failure spiral. The first step, she says, is accepting unfairness as fact.

Robbins introduces a card game metaphor: everyone is dealt different cards, and you can't control someone else's hand. Winning means focusing on how you play your own cards, learning from other players rather than competing against them. She urges readers to apply Let Them to people who got luckier or further ahead, since envy only erodes confidence.

She then distinguishes two types of comparison: torture and teacher. Torturous comparison fixates on fixed attributes—beauty, body type, height, metabolism, family, innate talents—things no effort can change. The 30-second test identifies whether something is fixed; if it can't be changed, obsessing over it is self-torture. She cites psychological research on upward comparison destroying self-esteem, contrasting it with rarely used downward comparison, noting most readers are better off than much of the world.

To illustrate, Robbins shares how her older daughter Sawyer torments herself comparing her body, metabolism, and abilities to her younger sister Kendall, who has a different build and a naturally gifted singing voice. No reassurance from Mel can stop Sawyer; she must choose to release the comparison herself or miss the beauty of her own life and talents.

Robbins warns this kind of comparison can fuel eating disorders, addiction, shame, and mental health struggles, rooted in an obsessive need to control the uncontrollable. The remedy: Let Them live their life, Let Me focus on mine. She closes by teasing the second type of comparison—comparison as teacher—as a gold mine to be explored next.