The Joe Dispenza meditation, specifically the work derived from Breaking the Habit of Being Yourself , is the hacksaw.

Your personality is a "program" composed of how you act, how you think, and how you feel. If you think the same thoughts, you make the same choices. If you make the same choices, you demonstrate the same behaviors. Those behaviors create the same experiences, which produce the same emotions.

Our personalities are essentially "muscle memory." We react to stress, anger, or joy automatically because the connection between the neocortex and the limbic system is hardwired.