When was the last time you wrote a thank-you note to someone? If you can’t remember the last time you sent one, a recent study may explain why. According to the new research, people chronically underestimate the power of expressing gratitude and overestimate how awkward it will be, which may keep them from engaging in the practice. This is a shame because expressing gratitude has consistently been shown as something that’s good for your health, mood and general well-being. In fact, it’s one of the easiest things you can do to increase your mental health.