Be shrewd, but not too shrewd. Your reflectiveness is not something to be affected, much less detected by others. All artfulness must be concealed, for it is suspect, especially that of foresightedness, which is hated. Deceit fills the world, so be doubly suspicious without letting it be seen, for that would destroy trust in you. Suspicion vexes the spirit and cries for revenge, awakening evils of which no one dreamed. To have considered well how to proceed is of great advantage for the day’s work; there is no better evidence of a person’s good sense. The perfection of an undertaking lies in the masterly sureness with which it was executed.
~ Baltasar Gracian, The Art of Worldly Wisdom (1647)