If you fell and scraped your knee the first time you attempted riding a bike, you wouldn’t say, “Something is horribly wrong with me. I don’t have the willpower and discipline required to ride my bike,” would you?

That would be silly. Instead, you’d realize that you just haven’t fully developed that skill yet. You’d think about why you fell. Perhaps you didn’t know how to navigate your bike through new terrain, such as a bumpy road or a patch of grass.

via Fitness Is a Skill, Not a Talent: Here’s How to Develop It.