Your point seems a valid one yet we may differ in thinking those activities need not be an enjoyable experience.

It is said that 10,000 hours of practice are required to become sufficient in a subject.

Do you think guitar players bemoan practicing? It is likely they overlook other duties to practice because they like to soo much.

The same can be said for all of the arts from painting to writting. Those that put their 10,000 hours in may oft times say they were driven to it not forced by dicipline.

My time spent in french immersion in Moroc was soo much more fun and more productive than in the restricted dicipline of the classroom.

Sometimes we don't choose our passions, they choose us and when they do dicipline is replaced by drive. Dicipline may be needed, more, by those lacking passion, like a forced piano lesson or gymnastics class.