If you have a serious face, you have to use 64 muscles on your lips. And if you smile, only 10 of your lips muscle is used. Small effort and you could take an advantage from that.
When you start smiling,
Your cheek will send messages to your brain.
At the same time, happiness hormones spreads and it will stop the production of stress hormones like cortisol and adrenalin.
It also triggers your immunity system which strengthen your body and produce antibody.
You don't have to worry if your smile is only to make others happy and not from your heart. The interesting fact is that your brain can't identify what kind of smile you've made. It means that a big smile is always a good one since happiness hormones will always be spreaded. What is the easiest thing to start a smile? You can try this tip.
- Try to look at your face in a mirror for a couple seconds. You will smile or even laugh after a while, laughing at yourself. By then, you should feel the happiness hormones spread out from your body.
So, what are you waiting for, try it and be happy. :)