If you're busy regretting the past, then a new future can't come in.
You're not to wallow, but if you don't process your regrets, then they remain emotional underground toxins.
If you did something in 1975 that you deeply regret and that you now can recognize as having been profoundly irresponsible, for example, the only way to be lifted out of deep regret and the pain over it is through atonement - through the kind of remorse that leads to genuine atonement, the making of amends, and forgiveness of self and others.
