A clever general... avoids an army when its spirit is keen, but attacks it when it is sluggish and inclined to return. This is the art of studying moods. Disciplined and calm, he awaits the appearance of disorder and hubbub among the enemy. This is the art of retaining self-possession.
Sun TzuLike the sun and moon, they end but to begin anew; like the four seasons, they pass away to return once more.
Sun TzuSomeone unfamiliar with the mountains and forests cannot advance [the team]. One who does not employ local guides cannot gain the advantage.
Sun Tzu