It is a good thing for us to cultivate our aggressive spirit. Life requires participation, and participation demands endurance and adrenaline; and he who enters battle with a spirit of meek submissiveness is likely to get precisely what he asks for. All this is true. Yet the patient endurance of the pack-mule may be just as valuable as the explosive fury of the panther: the former triumphs by being able to endure, while the latter may find itself fatally exhausted once its initial burst of energy is spent. Life more often demands the ability to absorb punishment than the ability to deliver it to others.