Evading self-acknowledgment of our faults enables us to avoid painful moral emotions: guilt and remorse for harming others; shame for betraying your own ideals; self-contempt for not meeting even our minimal commitments. We also bypass the sometimes onerous task of abiding by our values and manage to sin freely and pleasurably. We avoid the need to make amends and restitution for the harm we do. And, above all, we maintain a flattering self-image while pursuing immoral ends, often in the name of virtue.
Mike Martin, Self-Deception and Morality, pp. 37, 38.