Most people think of forgetting as a serious drawback. But to me, it has a great advantage. If you did not forget, it would be utterly impossible to serve God.
You would remember your entire past, and these memories would drag you down and not allow you to raise yourself to God. Whatever you did would be constantly disturbed by your memories of the past.
The past is gone forever and need never be brought to mind. Because you can forget, you are no longer disturbed by the past.
Rebbe Nachman’s Wisdom #26, by Reb Noson of Breslov