According to Queen Marguerite de Navarre, the author of the Heptameron, the secret to a happy life is simple.
Marguerite was one of the most accomplished women of the Renaissance: well educated and shrewd, a diplomat and wise ruler, who did much to sponsor the intellectual and artistic awakening of the period. Marguerite de Navarre offered this advice, or recipe, on the ingredients to lead a happy life:
Three ounces are necessary, first of Patience, then of Repose and Peace; of Conscience a Pound Entire is Needful; of Pastimes of all sorts, too, should be gathered as much as the hand can hold; of Pleasant Memory and of Hope three good drachms there must be at least. But they should moistened be with a liquor made from True Pleasures which rejoice the heart.
Then of Love's Magic Drops a few -- But use them sparingly, for they may bring a flame which naught but tears can drown.
Grind the whole and mix therewith of Merriment an ounce to even. Yet all this may not bring happiness except in your Orisons you lift your voice in praise to Him who holds the gift of health.
Basically Marguerite de Navarre's advice on how to be happy is this: you need Patience, Rest, Peace, Conscience. Pastimes, True Pleasures and Love (but use sparingly) and health. Timeless advice that we would do well to heed.