That definition almost perfectly describes qualities every successful person possesses, because mental toughness builds the foundations for long-term success. Successful people are great at delaying gratification. Successful people are great at withstanding temptation. Successful people are great at overcoming fear in order to do what they need to do. (Of course, that doesn’t mean they aren’t scared; that means they’re brave. There’s a huge difference.) Successful people don’t just prioritize; they consistently keep doing what they have decided is most important.