Our debt is paid. Paid for in blood on a cross. Paid for by a King. Given to us freely. The only requirements are that we repent and believe. We don't have to become perfect (simply because we can't), but we do have to make an honest effort.
Once we have made that commitment, repented and asked for the courage and strength to walk the path the Lord has laid before us, we see in ourselves all the ugliness that is sin. We do regret; that, too, is human nature. We regret the sins of pride and of anger, the thoughtlessness of our hearts. We strive to be "better people" and to live a life more pleasing than the one we've led up until that moment the the saving grace of Jesus is realized within our complex minds.
Often our failures and our past mistakes taunt us. The enemy uses them to distract us and when we begin the cycle of beating ourselves up again for past sins, we risk repeating them. We forgive ourselves, know in our hearts that we have been forgiven by God, yet still revisit the scene of past crimes in our head - torturing ourselves with the memories, wishing we could change them and right the wrongs, wanting to go back in time and repair the damage, take back the words or actions and maybe even choose a different road. We seek perfection in our own lives. We lay demands on ourselves that are impossible for us to achieve. We set ourselves up for defeat.
Go forward. Going back is not an option and no matter how many times you replay any situation, any decision and any outcome in your mind, the results remain the same. Look to changing what is yet to come. Learn from your past mistakes. Know that all you need to do is ask for that same courage and strength that you asked for when you began your journey. It is always there. It is always available. Remember the "old" you but do not revisit those dark days. Tuck it away and lift up your head. Walk in the direction of the cross - that is where you will find peace. That is where your Savior waits!