Have you ever failed in trying to live up to your Christian ideals?
Is the failure yours, or that of your Christian ideals?
Of course, the difference is that Christian ideals come from a flawless person - Jesus Christ - who spoke nothing but absolute Truth about life, God, and our relationship to God. His teachings and commands are absolutely authoritative and unassailable. The only true philosophy. Thus, there is a difference between deviation from a false philosophy and deviation from the true philosophy.