We all laugh, and because of so many different things – some of us like subtle jokes, others prefer crude jokes, mishaps, visual and other types of humor. Laughter is not just a human thing, some primates also laugh (and probably at our expense). Babies laugh an average of 300-400 times a day and adults laugh about 15-20 times a day. Laughing has been proven to be beneficial to our health, both physical and mental, but is it also contagious? Watch what happens when this man starts laughing for no reason at all! Try, if you can, not to laugh as well...
