My mom's house has always had a copy of the Serenity Prayer hanging on the wall, and I vividly and fondly remember the prayer being recited at AA meetings as a child. As an adult, I try to look to the prayer as a model. As an atheist, I interpret the message a tad differently, but the overall content is the same. I often find myself saying:
I will achieve serenity when I accept that there are things I cannot change; I will have the courage to change the things I can, and over time, I will acquire the wisdom to know the difference.