Research has shown that carrying out the physical activity of smiling will actually trigger the hormones and so on in our bodies that are associated with happiness. In other words; if we smile, we become more inclined to be happy. We sometimes go about our lives as if things happen to us rather than realizing the full extent of our power to control what happens – especially when it comes to our disposition. This information is extremely important for those of us who want to understand what it really takes to live an intentional life. Developing the discipline to choose our behaviors is the most powerful tool we have to forge our own internal reality – one that we have a measure of influence over rather than one that is controlled by external circumstance alone.
It can be very tough and counter-intuitive to think that we will improve our lives if we behave as we would “want to be” instead of “how we are”. We often feel such things as not caring, or anger and we behave according to these feelings – as if our emotions determine behaviors. What we often ignore is the power of behaviors to control emotions. If we smile long enough, we will be more inclined to be happy. If we discipline ourselves to behave as if relationships matter, and that we care, the hormonal cocktail that shapes our experience of life will actually begin to align around these behaviors.
This is not to imply that the effects of existing habits are not a powerful force. Repeated behaviors develop their own mass and momentum to be sure. We have to recognize that this emotion followed by behavior cycle can be a self-reinforcing feedback loop. This is why it is important to recognize that making behavioral choices despite our current emotions can have the effect of putting us in the driver’s seat, rather than a spectator in our own lives – otherwise we are destined to be a slave to habits which color our lives in ways we would not choose. The point is we can forge a more intentional self out of the currents of existing habit.
 “Facial Efference and the Experience of Emotion” by Pamela K. Adelmann and Robert B. Zajonc.