I highly recommend that you watch this video by A.J. Jacobs, a journalist from New York who tried to spend one full year of following every rule in the Bible. It’s quite interesting, regardless of your religion.
One of the comments that stood out for me in this discussion is how you can change your thoughts with your behavior. For example, when you smile, you get happier, or when you donate to charity, you become compassionate. So as much as we can change or improve ourselves inside out (changing our thoughts to change our behavior), we can also change from the outside in. Shows the power of action and how it can resonate back into our psyche. Anyways, enjoy the clip!