I think that twelve step programs can be a powerful tool for a person seeking to change their mind, reframe a worldview and disrupt problematic behaviors. It is not perfect, it certainly can be problematic for some people and is generally oozing with cringe, especially if you have not personally known an addict.

I like your assessment of the serenity prayer and i think the power of some of the common mottos are underestimated from a psychological perspective.

Related to the post the phrase Just for Today similarly helps resisting temptation by setting a smaller obtainable goal 'i don't have to quit forever, just for today' which relieves a lot of pressure but it also has another effect, a sort of psychological trick in that every day is 'today'.