Ability, motivation and attitude
Just because you can do something doesn't mean you will do it well - or do it at all. As humans, we do things that we are motivated to do. But then, there is a third ingredient, which might be the most important of the three. Our attitude determines if what we do is half hearted, or if we put our whole selves into it. We choose our attitudes.
If you want to do well at something, make sure your attitude aligns.