Epictetus is one of three Stoic philosophers we profile (Marcus Aurelius and Seneca are the other two) and this former slave turned leading philosopher of his era is incredible. He echoes the wisdom of all the great teachers as he reminds us that, if we want to be happy, we've gotta realize the only thing we have control over is our response to a situation. We'll have fun tapping into a lot more of his vast mojo in the Note.