The authors conjecture that to understand normal stress regulation, including cortisol stress reactivity, it is important to understand why these biomarkers are released and what they function to accomplish within the individual. This perspective holds that high (or rising) cortisol has advantages and disadvantages that must be understood within a context to understand how individual differences unfold. This perspective is juxtaposed with a popular vantage point of this stress hormone or of stress exposure that emphasizes the deleterious consequences or problems of this hormone. While the costs and benefits of cortisol are emphasized for normal stress regulation, this dynamic context-dependent purpose of stress hormones should extend to the development of psychopathology as well. This functional and dynamic view of cortisol is helpful for interpreting why Tackett and colleagues (2014) appear to observe advantageous cortisol recovery from stress in individuals with elevated personality disorder symptoms.