This document outlines how practicing positivity for 21 days can rewire your brain to be more optimistic and productive. It discusses how positive thinking leads to a "happiness advantage" where your brain performs better, with increased intelligence, creativity, and energy. Specifically, it states that positive thinking leads to 31% greater productivity, 37% better sales performance, and doctors making diagnoses 19% faster and more accurately. It then describes five exercises - writing down daily gratitudes, journaling positive experiences, exercise, meditation, and acts of kindness - that can be done for two minutes each day to train the brain to adopt a positive outlook.