Reorientation of activities and self-environment integration: this is a novel theory of activities that emerged from an intervention called multiple activities change intervention. This theory of activities divides activities into restoration, growth, and adjustment related activities. It uses pie-charts to quantify these groups, which are similar to the groupings of needs―and the similarities and differences between activities and needs and their classifications have also been discussed. Pie-charts called activities-circles help us in elucidating the most important principles of the theory: imbalance of activities, reorientation of activities, principal reorientation related activities, and self-environment integration. Personality is considered an offshoot of activities, and the theory of activities seems to have parallels with Big-Two and Biggest-One of Five-Factor framework. The new theory has also been compared with Apter’s reversal theory―and personality “enhancement” with prescription drugs has been analyzed in its perspective. Finally, I have tried to analyse the potential effects of related interventions on society in general and medicine in particular.