“Our belief systems, or personal stories, dictate our behavior. The stories we spin about ourselves can shape everything from the decisions we make to how we interact with others to the goals we accomplish. ‘Our thoughts have tremendous power and largely create our realities,’ said Joyce Marter, LCPC, a psychotherapist who writes the Psych Central blog The Psychology of Success. Negative, self-critical beliefs can create a self-fulfilling prophecy, she said. For instance, if we don’t think we will get a promotion, we probably won’t, ‘because we will not feel deserving and will not present in the best possible way and will self-sabotage.’ Our belief systems can produce and spike stress and undermine our ability to cope with challenges and stressors in our lives.”