Playing well is fun.
Often true, but not always. My DD had an experience where the culture of the team she was on sucked the fun out of the game for her, and she was very close to quitting the sport completely. A break for a few months, and a new team, helped her find her love of the game again.
Through it all, she never stopped hitting. Going to the park, and blasting balls high and deep is fun for her.