A quote
This is sound practice,—to refrain from associating with men of different stamp and different aims. And I am indeed confident that you cannot be warped, that you will stick to your purpose, even though the crowd may surround and seek to distract you. What, then, is on my mind? I am not afraid lest they work a change in you; but I am afraid lest they may hinder your progress. And much harm is done even by one who holds you back, especially since life is so short; and we make it still shorter by our unsteadiness, by making ever fresh beginnings at life, now one and immediately another. We break up life into little bits, and fritter it away.
Seneca·Letter 32 — On Progress (§2)·trans. Gummere