A perfect man would never act from a sense of duty; he’d always want the right thing more than the wrong one. Duty is only a substitute for love (of God and of other people) like a crutch which is a substitute for a leg. Most of us need the crutch at times; but of course it is idiotic to use the crutch when our own legs (our own loves, tastes, habits etc.) can do the journey on their own.