“People do not drift toward holiness. Apart from grace-driven effort, people do not gravitate toward godliness, prayer, obedience to Scripture, faith, and delight in the Lord. We drift toward compromise and call it tolerance; we drift toward disobedience and call it freedom; we drift toward superstition and call it faith. We cherish the indiscipline of lost self-control and call it relaxation; we slouch toward prayerlessness and delude ourselves into thinking we have escaped legalism; we slide toward godlessness and convince ourselves we have been liberated. -D.A. Carson
Why is it that we make excuses for every little sin? It is because we are not gravitating towards holiness, but away from it. It is as if we are sliding down a playground slide, but there are spots on the slide where we need to dust it off to make it slippery again. So we make excuses, dust the slide off, and continue to slide away from God, picking up speed the longer we go without God putting his hand down and pulling us back up towards him.