From Chapter Five - "Perfectionism, Virtue, and Self-Acceptance" of Everything Has Two Handles:
"Be not disgusted, nor discouraged, nor dissatisfied, if you do not succeed in doing everything according to right principles; but when you have failed, return back again . . ."
~ Marcus Aurelius (Long, 86)
Much in the spirit of the Talmud's "It is not up to you to complete the task, but you are not free to desist from it" (Pirke Avot 2:21) (which is quoted in this chapter), the endeavor is important even if we fail. In theory, our Stoic practice should be on of the few things "under our control," but many of us find that in reality, circumstances and our flawed perception of them leads to failure there, as well. Unless you are the Sage, the legendary perfectly-wise person of Stoic lore, you will make mistakes. And when you do, the important thing is to return to your practice. When you fall, you pick yourself up again and carry on.
"It is the action of an uninstructed person to reproach others for his own misfortune; of one entering upon instruction to reproach himself; and of one perfectly instructed, to reproach neither others nor himself."
~ Epictetus (Bonforte, 92)
". . . You might be objecting at this point that, without assigning blame, nothing would ever change or improve. But this highlights the difference between reproach - with its moral implications of rebuke and censure - and assigning responsibility . . . Of course, there are instances in which we justifiably find fault with ourselves and others - and the Stoic view of Epictetus should not be construed as license to 'do anything' without repercussion. Rather, the Stoic attitude tempers our moral judgments with the wisdom of the human condition and all its foibles - the knowledge that it is best to 'Forbear to judge, for we are sinners all' (Shakespeare, Henry VI, Part Two, III.iii.31) . . . "
"Marcus Aurelius tells us, 'Little the life each lives, little the corner of the earth he lives in, little even the longest fame hereafter . . .' (Farquharson, 15). And he adds - in his usual unvarnished manner - 'in a little while, you will be no one and nowhere' (Farquharson, 53). These sentiments may be seen as a counterbalance to those of the preceding section, in which we are admonished to revere ourselves as aspects of the Divine. There is no contradiction between these contrasting views of man. We are irreducibly divided beings - at once eternal and evanescent, divinity and dust. Montaigne put all this more earthily, 'Upon the highest throne in the world, we are seated, still, upon our arses' (in de Botton, 126)."