" Being social also increases levels of positive emotion—nurturing relationships, interacting and communicating with friends, helping people, engaging in group leisure activities, and both giving and receiving advice and encouragement from others.[38] And then there is exercise, which not only promotes happiness but also lowers stress and provides many physical benefits. Positive emotions might have evolved to give our ancient ancestors a survival advantage, but to experience them still enhances our lives today. "
― Leonard Mlodinow , Emotional: How Feelings Shape Our Thinking