Reading a short memoir of Antoine de Saint-Excupéry (letters to a hostage) I came across a wonderful description on the power of smiles:
"The essential, most often, has no weight. The essential there, was apparently nothing but a smile. A smile is often the essential. One is paid with a smile. One is rewarded by a smile. And the quality of a smile might make one die. This smile though took away the fear of the present. It gifted us security, hope and peace."
Antoine de Saint-Excupéry