Spending hours on the court practicing tennis or hours and hours practicing drumming does not turn tennis or drumming into work.
I can assure you
Well you don't have to be a pro athlete or a musician to do something "fun."
Like my chinese fortune cookie sometimes says: Choose a job you love, and you will never have to work a day in your life.
I think Confucius said that. And there are many people out there who live what they do for a living.