I believe that 12-step programs leave much to be desired and have much space in which to improve and adapt. Yet, I give credit where earned, and this snippet from page 417 of the Big Book of Alcoholics Anonymous profoundly and positively impacted my life:

"And acceptance is the answer to all my problems today. When I am disturbed, it is because I find some person, place, thing, or situation — some fact of my life — unacceptable to me, and I can find no serenity until I accept that person, place, thing, or situation as being exactly the way it is supposed to be at this moment. Nothing, absolutely nothing, happens in [the universe] by mistake. …unless I accept life on life’s terms, I cannot be happy. I need to concentrate not so much on what needs to be changed in the world as on what needs to be changed in me and my attitudes."

Acceptance does not mean turn the other cheek regarding either a person or the world. It means, in this respect, do not let the situation eat you up inside. I can solve any personal problem I face, no matter how dire, simply with a change in attitude.