When my cats aren't happy, I'm not happy. Not because I care about their mood but because I know they're just sitting there thinking up ways to get even.
Those who come a hundred or two hundred years after us will despise us for having lived our lives so stupidly and tastelessly. Perhaps they'll find a means to be happy.
True happiness comes from having a sense of inner peace and contentment, which in turn must be achieved by cultivating altruism, love and compassion, and by eliminating anger, selfishness and greed.
Different men seek after happiness in different ways and by different means, and so make for themselves different modes of life and forms of government.
Happy will that house be in which the relations are formed from character; after the highest, and not after the lowest order; the house in which character marries, and not confusion and a miscellany of unavowable motives.