Why should I smile when there is no joy in me? The answer to that is: Smiling is a practice. There are over three hundred muscles in your face. When you are angry or fearful, these muscles tense up. The tension in these muscles creates a feeling of hardness. If you know how to breathe in and produce a smile, however, the tension will disappear - it is what I call “mouth yoga.” Make smiling an exercise. Just breathe in and smile - the tension will disappear and you will feel much better. - Thich Nhat Hanh