Am I smart enough? Sexy enough? Successful enough? Self-doubt can eat away at our ability to function well in the world and share our many gifts. Which is why drowning out the negative voices inside our heads—and replacing thoughts of unworthiness with a steadfast belief in ourselves—is essential to growth, to moving forward in our lives, and, ultimately, to reaching our true potential. Fortunately, once we start to notice them, we can turn them around. But don’t delay: “Whether you are 20 or you are 70,” asks one TED Talk presenter, “can you afford one more day entertaining your self-doubt?”