Why do we complain of Nature? She has shown herself kindly; life, if you know how to use it, is long. But one man is possessed by an avarice that is insatiable, another by a toilsome devotion to tasks that are useless; one man is besotted with wine, another with is paralyzed by sloth; one man is exhausted by an ambition that always hangs upon the decisions of others, another, driven on by the greed of the trader, is led over all lands and all seas by the hope of gain...many are kept busy either in pursuit of other men's fortune or in complaining of their own; many, following no fixed aim, shifting and inconstant and dissatisfied, are plunged by their fickleness into plans that are ever new; some have no fixed principle by which to direct their course, but Fate takes them unawares while they loll and yawn- so surely does it happen that I cannot doubt the truth of that utterance which is greatest of poets delivered with all the seeming of an oracle: "The part of life we really live is small." For all the rest of existence is not life, but merely time.
You live as if you were destined to live forever, no thought of your frailty ever enters your head, of how much time has already gone by you take no heed. You squander time as if you drew from a full and abundant supply, though all the while that day which you bestow on some person or thing is perhaps your last. You have all the fears of mortals and all the desires of immortals. You will hear many men saying: "After my fiftieth year I shall retire into leisure, my sixtieth year shall release me from my public duties. "And what guarantee, pray, have you that your life will last longer? Who will suffer your course to be just as you plan it? Are you not ashamed to reserve for your self only the remnant of life, and to set apart of wisdom only that time which cannot be devoted to any business? How late it is to begin to live just when we must cease to live! What foolish forgetfulness of mortality to postpone wholesome plans to the fiftieth and sixtieth year, and to intend to begin life at a point to which few have attained!
-Adapted from Moral Essays by Lucius Annaeus Seneca