Yoko Ono, Film No. 5 (Smile)

"In Film No. 5 (Smile) Lennon smiles at the camera in slow motion, a variation on an early Yoko Ono sculpture called A Box of Smile [...] It was the sort of art you either meet halfway or fail to get entirely [...] But it was emblematic of the life-as-art philosophy. Smile into the mirror. That's all. A tiny prod of personal enlightenment, the art of positive consciousness."

The Accidental Masterpiece. On The Art of Life and Viceversa,  Michael Kimmelman