In "How to Stop Worrying and Start Living," Dale Carnegie emphasizes the importance of letting go of concerns that are beyond our control, a principle rooted in the teachings of the philosopher Epictetus. Carnegie illustrates how worrying can hinder our happiness and overall well-being, suggesting that true contentment comes from focusing on what we can influence in our lives.

The book encourages readers to adopt a more positive mindset by shifting their focus away from external factors that cause stress. By embracing this philosophy, individuals can lead happier, more fulfilling lives, as they free themselves from the burdens of worry and anxiety over uncontrollable circumstances.