Doing something new that I'm not good at isn't always fun.
Admitting when I'm wrong definitely isn't fun.
Writing is fun, except when it's not.
Sometimes, but not always, making your art is fun.
Fun is fine, it's just not to be trusted. It's not a very good way to measure whether you're doing the real work, whether you're doing something you'll be proud of in 10 years, whether you're living well.
Following the fun ... that can be dangerous.