The secret is, joy is Divine. Laughter eliminates stress, removes problems and heals the mind and body. Many religions say joy should be the natural state for everybody. But people get entangled in their thoughts/problems, negative emotions, wrong reactions/perceptions and unhappy experiences. If they don't clear their mind, they become miserable. So laughter quickly clears the mind. When a person stops taking everything and everybody so seriously, they can relax and live longer.