So I was telling Matt yester eve about a book that Andreia brought me back a few years ago from her time in Vietnam: Peace is Every Step by Thich nhat hanh.
Matt had definitely already been introduced to hanh's work, and so I re-read a section that I remembered near the beginning:
"A tiny bud of a smile on our lips nourishes awareness and calms us miraculously. It returns to us the peace we thought we had lost" (hanh 7).
What a fine and simple reminder of how great the smile is.