A joke is a very serious thing.
Winston Churchill, Sir (1874-1965) 

Ask yourself whether you are happy and you cease to be so.
John Stuart Mill 

Blessed is he who has learned to laugh at himself, for he shall never cease to be entertained.
John Powell 

Common sense and a sense of humor are the same thing, moving at different speeds. A sense of humor is just common sense, dancing.
Clive James 

Happiness is good health and a bad memory.
Ingrid Bergman (1917-1982) 

Happiness is inward, and not outward; and so, it does not depend on what we have, but on what we are.
Henry Van Dyke 

Happiness is not having what you want, but wanting what you have.
Rabbi H. Schachtel  , The Real Enjoyment of Living

Happiness is the only sanction of life; where happiness fails, existence remains a mad and lamentable experience.
George Santayana (1863-1952) 

He who laughs last didn't get it.
Helen Giangregorio 

He who laughs last has not yet heard the bad news.
Bertolt Brecht