When one person suffers from a delusion it is called insanity; when many people suffer from a delusion it is called religion. (Robert Pirsig)

The full use of your powers along lines of excellence. (definition of happiness by John F. Kennedy)

All are lunatics, but he who can analyze his delusion is called a philosopher. (Ambrose Bierce)

I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth. (Umberto Eco)