"I can't believe I just said that." "What possessed me to do that?" "What's wrong with me?" We're constantly seeking answers to these fundamental human questions, and now, science has the answers. The foods we enjoy, the people we love, the emotions we feel, and the beliefs we hold can all be traced back to our DNA, germs, and environment. This witty, colloquial book is popular science at its best, describing in everyday language how genetics, epigenetics, microbiology, and psychology work together to influence our personality and actions. Mixing cutting-edge research and relatable humor, is filled with fascinating insights that shine a light on who we really are—and how we might become our best selves.