Reinforcement learning - Wikipedia
We all this in our lives — the picture-perfect way to live that won't breed regret. We know it won't always happen, because sometimes the wrong decisions are just made. Sometimes, life just happens. To help us, though, communication is an essential part of our every day with others, or even with that inner voice that tells you to stay clear of situations, a relationship, or that financial decision that has done nothing but bring your trouble.
Oregon Social Learning Center - Science benefiting families

There's no regret for that kind of sorrow
I have corrected some of the other grammar in that sentence :)
I would like to express my regret for the incident that happened yesterday in my room, for which Mark complained to you.If you are really sorry about what happened in your room, you could use:
I would like to express my sincere regret
Understanding Social and Emotional Development in Preschoolers
How do we live a regret-free life? Happify offers this: Live a life that feels meaningful to you and not one based on the expectations of others; have the courage to express your feelings; allow yourself to be happier; prioritize family time over long hours at the office; and stay in touch with old friends.
