I messed up a lot growing up. I certainly made more than my share of bad decisions. My parents are/were well aware. I felt bad about them, felt guilty and felt ashamed. But my parents always let me know they loved me. They never mentioned those things again. They had forgiven me and moved on. This helped me to begin to understand God's grace! Grace is not just undeserved favor but it is God power to help us do better.
We all know someone who seems to do bad things, Jesus is not in their life and yet, everything seems to fall into place for them. Satan can bless too. The more money, power, things they get the more they don't need God. They think they are self sufficient. People who have no foundation of faith can easily be manipulated. In Matthew 4: 9, Satan told Jesus, "All this I will give you,' he said, 'if you will bow down and worship me.'" These people may have "things" but they do not have joy or peace. They cannot be satisfied.
If you are blessed by God's grace you are very thankful and humble. You are not selfish and because you have the Holy Spirit in you, you desire to bless others. You want to continuously thank God because you know all good things come from Him. James 1: 17, "Every good and perfect gift is from above, coming down from the Father of the heavenly lights, who does not change like shifting shadows." As a child of God we know we are given grace upon grace!