None of us is perfect. No matter how hard we try. We are human and humans make mistakes. In the Bible Paul says I do the things I ought not and don’t do the things I should. This is true of everyone.
The things that most of us do wrong are usually not serious but can hurt others. Hopefully, we don’t really want to hurt anyone. The thing that is hard to take is that there are some who really do want to do harm. There are many explanations why this happens. Most of us want to believe that they are damaged in some way. Many of them are. The shooter in New Zealand may have been taught the hatred he exemplified.
There are those that were damaged by the treatment they received as children. The things that happen to us in the early years can leave some terrible scars. Some people are able to recover and make peace with themselves. Some are not and that past pain is reflected in their treatment of others.
In my lifetime I have had the experience of meeting a few whose earliest lives created true monsters. There are theories for why this happens… some about early bonding. One of my friends adopted two infants from mothers who were addicted to crack cocaine. One of them did well but suffers from some physical problems. The other was diagnosed as a sociopath. ( I think now called antisocial disorder) As early as preteen the rooms of the other family members had to be locked in fear of his actions. They tried everything they could to help but to no avail. This very loving family was able to keep him until his teen years and at that point safety for the family required letting him go. I know he was in treatment for a while but I don’t know where he ended up. God help those where he is.
Every one of us has done things we regret and wish we could fix. We would like to go back and change everything. We may not be able to do that but we can go forward with a desire to do better. Doing our best to respect and understand those around us can make a difference.
If you have things you need to let go confess them. Whether to God, your own higher power or even to yourself. Acknowledge your mistakes and move on. Forgiveness heals.