G-d said to Noah, "I have decided to put an end to all flesh."
G-d did not bring on the Flood because He suddenly realized that He made a mistake by creating the world. Rather, the pre-Flood and post-Flood realities were necessary stages in the world's development, stages that are reflected in every individual's life.
Before the Flood, reality was locked into the irresistible forces of cause and effect. Every good choice reinforced goodness permanently; every bad choice reinforced evil permanently.
The Flood softened reality by introducing the opportunity of repentance. Thus, when Noah emerged from the ark, what he beheld was not a ruined, post-apocalyptic devastation, but a new, fresh, world, full of promise and free from the shackles of the past.
In our own lives, too, we can mistakenly think that we are inescapably locked into a destiny dictated to us by our heredity, our upbringing, or our own prior errors. Because of the Flood, the exact opposite is true: it is never too late. G-d is always waiting to welcome us back with open arms to begin anew. Repentance, like the Flood, enables us to transform any challenging situation or turbulent phase of our lives into a means to cleanse us, refine us, and prepare us to carry on with greater faith and strength.
--From Daily Wisdom