Should I be interested in creating a work of art if i don't understand the theory behind it entirely?
Yes, I think most beautiful works of art come from a combination of experience and intuition, and not so often deliberate explorations of technical theory.
how many of you guys create music purely from ear?
I doubt anyone does (although I recommend trying!). You will always build up a set of concepts, ideas and patterns from just making music (you probably do it intuitively and subconsciously) that you will come back to when you're composing the next time. If you are a human, you will analyze and theorize about most everything you do whether you want to or not.
what do I do about the anxiety of being imperfect?
Take some time to realize that nothing is perfect. What makes a song perfect for you? Also keep in mind that imperfections can highlight beauty.
EDIT: I think we need to define what "purely from ear" means. Literally speaking, it makes no sense of course, but I think that InactiveX and I are a few steps apart in our definitions. What I meant to say is that there's always some knowledge you build upon when creating music (or kicking balls), whether you read it in some book, heard it, found out by practice or were inspired by something else. I don't really believe in ultimate originality, and there's no such thing as making something up out of the blue, which I'm sure InactiveX will agree with. Just so that's clear 
I guess that InactiveX interpreted the question more like "how many of you guys create music purely by intuition?" while my own interpretation was really too literal to be of any use at all.
