I often find that people that say this don't really mean it or don't understand regret. Regret is feeling sorry for something you did wrong. So either you have never done anything wrong OR you don't feel sorry for doing wrong which is a lot worse than living with regret. I would also think and hope that if you had your life to live over, knowing everything you do know, that being in the exact same situation again where you were wrong, you would make a different decision. That is why regret can be good because one day you may find yourself in a similar situation as one where you were wrong and from that regret you can choose to make a better decision, becoming a better person. Without regret, you will keep making the same bad decisions over and over. It is only the man who wishes to better himself that accepts his regret and uses it to become a better person.