In this link you’ll read:
While in the hospital Cousins hypothesized that if negative emotions such as anger and frustration could contribute to poor health, why couldn’t positive emotions such as joy and laughter have the opposite effect?
http://www.joeyguse.com/2007/07/how-marx-brothers-brought-norman.html?m=1
I offer you the following video (that truly warms my heart) in honor of my dear boxer that I lost on Thursday.
Love you forever Josey Wales…
https://youtu.be/IYjCY6qVHCY