Contributions to Nonlinear Analysis: A Tribute to D.G. de Figueiredo on the Occasion of his 70th Birthday (Progress in Nonlinear Differential Equations and Their Applications)

Laugh and cry. Having a good sob is reputed to be good for you. So is laughter, which has been shown to help heal bodies, as well as broken hearts. Studies in Japan indicate that laughter boosts the immune system and helps the body shake off allergic reactions.