"God grant me the serenity
To accept the things I cannot change,
Courage to change the things I can,
And wisdom to know the difference."
This simple, powerful prayer is one of the first things that I learned in Al-Anon and Adult Children of Alcoholics meetings.
From the book "Opening our Hearts, Transforming our Losses" written by Al-Anon Family Group Headquarters, Inc., page 173:
"Serenity doesn't come by avoiding the difficulties in my life, but by walking through them with the help of my Higher Power and my recovery friends."
Avoiding your difficulties in life is the same as living in denial and only works against you. Denial never solves anything. It just adds more challenges on top of what you are already avoiding.
The Serenity Prayer doesn't ask God to remove the situation or difficulty. It asks for help to change your reaction to the situation or difficulty. Sometimes the only thing that you can do is have the courage to realize that nothing but you can change. Changing the other person is never an option. The only person you can ever change is you. The other person is the only one who can ever change the other person. This kind of acceptance can bring you peace.
The Serenity Prayer is one of the most useful tools that I have ever found.