“There is no greater power than to smile at failure, no more beautiful an ornament to your being than a genuine smile, and no beauty greater than the smile of peace and wisdom glowing on your face.”
“Be a Smile Millionaire.”
~ Paramhansa Yogananda
So that smile is the genuine smile of inner Joy of being one with Atman
This smile is a reflection of realization. Which is of course rare
But those who have it can hide it also
Bhavin