The more sacred an idea is to us—that is, the more deeply it is tied to our identity—the more strongly we will defend it against criticism. You see this in every industry. The schoolteacher who ignores innovative teaching methods and sticks with her tried-and-true lesson plans. The veteran manager who is committed to doing things “his way.” The surgeon who dismisses the ideas of her younger colleagues. The band who produces a mind-blowing first album and then gets stuck in a rut. The tighter we cling to an identity, the harder it becomes to grow beyond it. One solution is to avoid making any single aspect of your identity an overwhelming portion of who you are. In the words of investor Paul Graham, “keep your identity small.” The more you let a single belief define you, the less capable you are of adapting when life challenges you. If you tie everything up in being the point guard or the partner at the firm or whatever else, then the loss of that facet of your life will wreck you. If you’re a vegan and then develop a health condition that forces you to change your diet, you’ll have an identity crisis on your hands. When you cling too tightly to one identity, you become brittle. Lose that one thing and you lose yourself.