Humility, a practical virtue.

Humility is so practical a virtue that men think it must be a vice.  Humility is so successful that it is mistaken for pride.  It is mistaken for it all the more easily because it generally goes with a certain simple love of splendour . . . .  In a word, the failure of this virtue actually lies in its success; it is too successful as an investment to be believed in as a virtue.  Humility is not merely too good for this world; it is too practical for this world; I had almost said it is too worldly for this world.

G.K. Chesterton, Heretics, quoted in The Quotable Chesterton, p. 153.