So that God may very well have pulled us all aside before mortality and said something to the effect of, “You have no idea what a pain in the butt it is going to be to get you from Point A to Point B. I’ve got a whole village of your brothers and sisters who have agreed to sacrifice their innocence so that they can blow off the frustration that is required to help CHANGE you. So…you’d best figure out how to forgive real fast.
And this makes sense because the Atonement, a principle already part of this plan, is God granting us forgiveness. And to personally understand how that process works, how the process cleanses one from their mistakes, an individual would have to understand psychologically how forgiveness works, applying it to a one who had wronged them, to then fully believe that forgiveness could actually work on them. Otherwise, you could tell someone who couldn’t conceive the power of forgiveness that they themselves had been forgiven through the atonement. But in that persons mind they’d be thinking “I’m forgiven. I don’t buy it.” Because to them the concept of forgiveness is impossible. To them, there is no psychological power strong enough to change the past.