Don't fear god, Don't worry about death; What is good is easy to get, and What is terrible is easy to endure. - Epicurus

A prudent man, in order to secure his tranquility, will consult his natural disposition in the choice of his plan of life. If, for example, he be persuaded that he should be happier in a state of marriage than in celibacy, he ought to marry; but if he be convinced that matrimony would be an impediment to his happiness, he ought to remain single.

Let no one be slow to seek wisdom when he is young nor weary in the search of it when he has grown old. For no age is too early or too late for the health of the soul. And to say that the season for studying philosophy has not yet come, or that it is past and gone, is like saying that the season for happiness is not yet or that it is now no more. Therefore, both old and young alike ought to seek wisdom, the former in order that, as age comes over him, he may be young in good things because of the grace of what has been, and the latter in order that, while he is young, he may at the same time be old, because he has no fear of the things which are to come. So we must exercise ourselves in the things which bring happiness, since, if that be present, we have everything, and, if that be absent, all our actions are directed towards attaining it.

Gentleness, as opposed to an irascible temper, greatly contributes to the tranquility and happiness of life, by preserving the mind from perturbation, and arming it against the assaults of calumny and malice.