Smiling can also have a positive impact on our longevity. A study found that people who smiled more often lived longer than those who didn't. This may be due to the fact that smiling can reduce stress, which is a significant contributor to chronic diseases like heart disease, diabetes, and cancer.

The Power of a Lovely Smile: How a Simple Gesture Can Brighten Up Your Day

Tension can make a smile look forced or "toothy." Take a deep breath and let your facial muscles soften. The Bottom Line

: This muscle pulls the corners of your mouth upward.