Sometimes your joy is the source of your smile, but sometimes your smile can be the source of your joy.
--Thich Nhat Hanh

Act enthusiastic and you will be enthusiastic.
--Dale Carnegie

Nearly everyone recognizes the effect our emotions have on our physical appearance. Anger forms a frown on your face, pain a grimace. What we often miss is that this works in reverse as well. Choosing to smile even when it is unnatural, can in turn create a happier mood in you. Acting joyful and enthusiastic can bring about joy and enthusiasm in you. Knowing this, it is completely in your control to bring about the emotions in yourself that you desire. You are in control.