The apostle Paul stated in Philippians 3:13, one thing I do [it is my one aspiration]: forgetting what lies behind and straining forward to what lies ahead. The word "straining" in the Amplified translation tells us that whenever we have to "press on" there will be opposition from the enemy.
Endings always bring new beginnings. Satan strives to keep us out of the new place that God has prepared. He wants to trap us in the past and cause us to live in permanent misery, which is what self-anger and self-blame will do.