" Research has shown that smiling releases endorphins—the happy hormones that shift your physiology for improved well-being. When you smile and your eyes crinkle, your body releases chemicals that change the chemistry of your brain, lifting spirits, and reducing pain. Even when it is hard to smile and you are forcing it, positive changes take place in your physiology. "

― Susan C. Young , The Art of Body Language: 8 Ways to Optimize Non-Verbal Communication for Positive Impact (The Art of First Impressions for Positive Impact, #3)