Real smile.

“Most smiles are born of good emotions arising out of good, or out of feeling sympathy, love and kindness, or mercy. But the most wonderful way to smile is to fill your heart with the love of God. Then you will be able to love everybody; you will be able to smile all the time. All other forms of smiles are evanescent because emotions flicker and pass away, no matter how good they are. The only thing that can last is the joy of God. When you have that, you can smile all the time.”