For more than four decades, my colleagues and I have examined how social contexts and individuals influence each other. To provide a perspective on this work, I describe some lessons we have learned: situational influence exemplifies both the power and fragility of social contexts; common aspects of settings underlie their power, for better and for worse; individuals' health and well-being is affected by powerful forces in eight domains; and intervention programs are powerful settings that encompass risks as well as rewards. I then note some unresolved questions, such as how to balance the risks and rewards of powerful environments, how to better understand the interplay between individuals and the social contexts they select and create, how to learn from the fact that many people overcome the power of traumatic social contexts, and how to apply our knowledge to balance the risks and rewards of individual and community contexts.