Remember the phrase, "Don't cry over spilled milk?"
We do, though. Actions bring guilt and wishes for a do over.
Do something wrong, and boom! Regrets descend like a Tsunami and might live with us forever.
What is the difference between guilt and regrets? Not much. They both relate to the past.
If we ask God to forgive us of sins and previous mistakes, He does. Do we forgive ourselves? Perhaps, but often, we don't. A personal pardon is a sticky situation. We are harsher on our person than God is.
Depending on our nature and upbringing, the degree of regret varies. For one person, a glass of spilled milk brings a brief moment of remorse, but for others, the hand trembles each time they pick up a glass of milk.
God forgives, so we should also pardon ourselves. Are we greater than God? Are we going to punish ourselves when God doesn't? That's an absurd thought, isn't it?
We are human. We remember, regret and feel guilty over actions God chooses to forget.
We can learn from past behaviors, but the past isn't the future, and agonizing over ancient actions wastes time and energy.