Lesson 1: Genes play a huge role in our optimism levels, but our thoughts can make or break our happiness .

Our genetic makeup creates a baseline for happiness . Additionally, our DNA determines whether we’re more likely to be more optimistic or pessimistic, for example, and whether we’re more likely to be extroverted or introverted . 

Our parents pass these traits down to us. And we can’t change it through any kind of intervention. Although our genes play a huge role in our natural dopamine levels, our thoughts are what really make us feel happy or sad.