Dogs laugh, but they laugh with their tails.
Humor is the instinct for taking pain playfully.
Laughter is, after speech, the chief thing that holds society together.
A smile is the universal welcome.
Laughter puts your brain, your central nervous system and your whole being into a state of free play.
Dogs laugh, but they laugh with their tails. What puts man in a higher state of evolution is that he has got his laugh on the right end.