It is necessary to challenge the self-limiting beliefs that prevent people from trying to improve their circumstances.

“If you're listening and there's an area of your life where you have basically said, "I've missed the window or I'm too late or I'm not capable of that." Professor Duckworth is going to tell you you're wrong.”

Effort is a critical variable in success because it is required both to develop skill from talent and to turn that skill into achievement.

“To me, skill is kind of barren unless you apply it, right? So, what are you going to do with your skill? Well, you need effort to sort of unlock your skill and turn it into actual achievement.”