Wrongs are often forgiven, but contempt never is. Our pride remembers it forever. - Philip Dormer Stanhope

As a man of sense never at∣tempts impossibilities, on one hand, or the other, he is never discouraged by difficulties: on the contrary, he redoubles his industry and his diligence, he perseveres, and infallibly prevails at last.

no pierdas tiempo, hijo mio, en formar tu gusto, tus modales, tu mente y todo lo que has de tener; pues lo que, hasta cierto punto, seas a los veinte anos, eso, con poca diferencia, seras todo el resto de tu vida

Common sense (which, in truth, is very uncommon) is the best sense I know of: abide by it; it will counsel you best.