Sometimes, it's writing. Although, sometimes writing can make me sick too. Other times, it's performing. It doesn't matter what it is either. It could even be teaching, which I consider a significant amount of to be performance, though not the majority. There's something about that moment when you know you've got someone hooked, where you'll lower your voice and they'll lean in to hear whatever it is, when whatever spell you've been weaving nears completion. Too much of that can be unhealthy too though, I think. It makes a person hungry for it.
I'm not sure if teaching is performance in general, but it totally is to me. Within the structure of the curriculum and the lesson plan, one of the most enjoyable aspects of teaching is working the room, finding ways to deliver the content in meaningful manner, connecting with your students, ensuring that everybody is on the same level, etc... If that's not performance, then...