Excusing ourselves is a human frailty. We do it all the time. Call it the human factor.
Some have stated that the other person committed a sin, whereas all they did was make a mistake. We have one set of standards for ourselves, but a different set for others, and will tend to overlook faults in ourselves while judging others.
If we were to look at ourselves as God sees us, we would see something very different. The prophet Isaiah thought he was a very righteous man, but when he saw the Lord, (Isaiah 6:1), he said, “Woe is me.” Later on in Isaiah 64:6, he stated that all our righteousnesses are like filthy rags.
You must get to the place where you are willing to have the Lord expose things in your life that are displeasing to Him. Spiritual maturity is only possible when you allow the Lord to cause changes to take place in you.
Psalm 139:23 Search me, O God, and know my heart; try me, and know my anxieties; 24 and see if there is any wicked way in me, and lead me in the way everlasting.