Start looking at the glass half-full! Keeping oneself in a good mood is likely to stretch your life span. Studies show that people with a positive way of looking at things—even just regarding the aging process—can increase their life span by seven years. Stress and negativity can lead to overall bad health, affecting the heart, immune system, and endocrine system. Choose whatever healthy mood-boosters you know work for you—such as reading a good book, baking cookies, or taking a relaxing bath.