I was thinking a bit more about that boredom thread, but as it didn't have to do with boredom any more, I'll post it here.
Doing things you love to do as a hobby and being happy with that: if that isn't something for an SJ! It seems to me, that you do your job, and you use your free time to relax and to reload yourself full of energy to be ready for your job again. If creativity is something you like to do, you do that in order to be happy, so you can be kind and good-humoured at work again.
I feel two things about that.
First: this is how things ought to be. Free time is designed to relax. Creativity is just a plaything, making you happy now and then. Again, you're right and I'm wrong.
Second: how can you stand losing so much free time?! Aren't you supposed to be the efficiency champions? You could do soooo much more! Why relax if you can be creative?