OPTIMISM, n. The doctrine, or belief, that everything is beautiful,
including what is ugly, everything good, especially the bad, and
everything right that is wrong. It is held with greatest tenacity by
those most accustomed to the mischance of falling into adversity, and
is most acceptably expounded with the grin that apes a smile. Being a
blind faith, it is inaccessible to the light of disproof -- an
intellectual disorder, yielding to no treatment but death. It is
hereditary, but fortunately not contagious.
-- Ambrose Bierce, "The Devil's Dictionary"