Worry is a negative emotion that results in physiological symptoms like increased heart rate and sweating, as well as negative emotions that distract from solutions. The document provides 4 ways to stop worrying: sharing concerns with others, getting facts to address worries, making a plan to tackle issues, and taking care of one's brain. It encourages following the "Hakuna Matata" principle of not worrying by getting up and doing something productive instead of lying awake with worries.