Regardless of whether it's "key" or "essential", the question becomes how does one get grit? Who and what helps to build the "passion" and "perseverance" necessary for success? These questions are important for any one at any age.
When I was 10 years old, my family uprooted and moved from Malibu, California to Minnetonka, Minnesota. My education was about to faceplant into a frozen pond of mundanity, a scholastic reversal that literally took years to rectify.
In preparation for one of our high school reunion many years after graduation, the chairperson of our reunion suggested that each of us write about the best time of our lives. I gave this careful thought and simply wrote: "The present is the best time of my life."