Self-discipline is the key to success. It is the force that helps us stay focused on our studies when we’d rather be partying. It’s the force that keeps us going to the gym when the couch beckons. It’s behind the determination to build the 147th prototype when the 146th version didn’t work.

In other words, self-discipline is the quality that pushes us to complete the tasks we know we should do in order to achieve our goals, rather than give in to momentary distractions that take us off course.