Smiling… not only lifts your spirits but that of those around you. A smile uses muscles that stimulate us to feel better. When you smile you feel better, even when you are feeling down.
“Sometimes your joy is the source of your smile, but sometimes your smile can be the source of your joy.” ~Thich Nhat Hanh
Our faces have muscles with the ability to animate our faces to 
express and to show how we feel, think and emote at any given time. Our feelings and emotions direct that animation of the muscles either naturally or they can be forced and faked. Take an actor for example: While acting they can use their body as an instrument to express feelings and emotions that will illicit feelings and emotions in those watching. We all have that ability in every moment and every day of our lives that will affect not only us but those around us.
I love to smile. I once had a surgery where my cheeks were swollen for a few weeks and I couldn’t smile. It was a horrible feeling not to be able to smile. It made me feel so down inside not to be able to smile. I so wanted to smile but couldn’t and my smile was distorted when I tried. I was amazed how not being able to smile affected my mood, my feelings and everything about me. Then when my face became less swollen, and I could smile a bit, I felt better. When I could fully smile again, I felt great! Smiling affected my whole body, my mood, my spirit… everything about me.
A smile affects your physiology and that of those around you.
That experience made me realize how wonderfully good smiling made me feel. It lifts me up and makes me feel so good inside. Think of people with bad teeth that don’t smile and children with cleft palates who can’t smile… when these things are corrected and they are able to smile… their whole face lights up. Their mood changes along with that of everyone around them. A smile affects the energy in your eyes, in your body, in everything about you. Smiling affects health and well-being.
You can smile with your eyes, your lips and with your whole face. There are all kinds of smiles. But a genuine smile lights up your eyes, your whole face and affects your whole body along with the energy it carries and emits.
The muscles of expression located around the mouth are the depressor anguli oris, therisorius, the zygomaticus major, the zygomaticus minor, and the levator labii superioris (see above image, highlighted in blue). All of these muscles, specifically the zygomaticus muscles, are involved with smiling; they pull the orbicularis oris (the circular muscle of your mouth) upwards. These muscles are innervated by the various branches of the facial nerve (VII), which — when the muscles are activated — send signals to the brain that you are smiling.
From there, endorphins are released into the bloodstream from the pituitary gland and the brain and spinal cord from the hypothalamus. Endorphins are opiod (chemicals that bind to opiate receptors) peptides that act as neurotransmitters. Think of endorphins as the body’s natural painkillers, or opiates; they are released in times of stress (good and bad), exercise, excitement, pain, love, and other emotional states, and you feel awesome because of them
http://info.visiblebody.com/bid/216820/learn-the-science-behind-a-smile-visualized-with-visible-body
Smile more. Smile lots. Smile at others. Smiling is contagious. When you smile it lifts the energy. A smile creates openness… a channel for positive communication.
Smile at yourself in your mirror. Lift your spirits along with those around you.
SMILE!