I won't just have a job; I'll have a calling. I'll challenge myself every day. When I get knocked down, I'll get back up. I may not be the smartiest … - Angela Duckworth

Without effort, your talent is nothing more than unmet potential. Without effort, your skill is nothing more than what you could have done but didn't.

Encouragement during the early years is crucial because beginners are still figuring out whether they want to commit or cut bait. Accordingly, Bloom and his research team found that the best mentors at this stage were especially warm ans supportive: 'perhaps the major quality of these teachers was that they made the initial learning very pleasant and rewarding. much of the introduction to the field was as playful activity, and the learning at the beginning of this stage was like a game'.
A degree of autonomy during the early years is also important. Longitudinal studies tracking learners confirm that overbearing parents and teachers erode intrinsic motivation. Kids whose parents let them make their own choices about what they like are more likely to develop interests later identified as a passion.

Staying on the treadmill is one thing, and I do think it's related to staying true to our commitments even when we're not comfortable. But getting back on the treadmill the next day, eager to try again, is in my view even more reflective of grit.