The most successful people have a high tolerance for pain. Not just physical pain but the pain of being misunderstood, the pain of slow progress, the pain of delayed results, of rejection, of starting over again and again. We celebrate success, but we rarely talk about what it takes. Many people quit not because they aren’t smart, but because they can’t handle the weight of the process. You think you're tired now? The people who made it pushed through tiredness. You think you're discouraged? Th…