Proverbs 18:17
We can justify ourselves to the point we really think we are clean in spite of our sins. We will use "all humanity" as our excuse, admitting we are sinners "just like everyone else," but not wanting to admit specific sins or faults lest we have to overcome them. God knows all men have sinned and fall short of His glory, but He is only interested in our repentance (change), overcoming, and growth, not our excuses. "Everyone is doing it" does not justify our personal sin. God will forgive only as we repent.