Serenity is not just for recovering addicts, although recovering addicts undoubtedly seek it in order to grow in victory and freedom, that is, to live as productively as possible without resorting to the addictive substance or practice. [Read the above link to blogger Msgr. Charles Pope of the Archdiocese of Washington, who writes well of serenity.]
The need for, and value of, serenity is universal. Who among us is not affected by sin and its consequences--the weakening of the will, the darkening of the intellect, and our tendency to be mastered by, and not master of, our emotions? Corollary to these consequences are a multitude of "dysfunctional" attitudes and attachments that beleaguer the human person and cry out for mercy.
Whether or not we care to admit it, most of us just need to make it through the day. That's what serenity is for.