Emotions are caused by brain chemicals we’ve inherited from earlier mammals. Each chemical has a job that's easy to understand from animal studies. Dopamine triggers a good feeling when you approach a reward. Serotonin makes you feel good when you get respect. Oxytocin feels good when you trust or receive trust. Endorphin masks physical pain with a euphoric feeling. These happy chemicals evolved to reward behaviors that promote survival, and were not meant to surge all the time. The let-down you experience when a happy-chemical surge passes drives you to seek things that meet your survival needs. Your brain defines that in a unique way individual experience builds the neural pathways that turn the chemicals on and off. Anything you experienced in youth built superhighways in your brain that shape you more than you realize. You can build new pathways to turn on your happy chemicials in new ways, but it's harder than you expect. This book guides you through that challenge. It helps you choose new happy habits that are right for you, and repeat them until new circuits build. If you repeat a new behavior for 45 days, the electricity in your brain will start surging down the new path. You will have a new happy habit and you'll be ready to start building another one.