Why does the spiritual life need structure instead of just doing what feels right?

The whole idea that you're going to make any progress in life without structure, on anything, is total nonsense. If you said, I want you to become a chemist, and I said, don't go to school, just read some chemistry books when you feel like it: what? No. If you want to get in shape, we don't say, hey man, just lift weights with your heart. The activities and the actions we put our hand to have a tremendously transformative effect on us, but we have to do them seriously and diligently. And that's what I found in Orthodoxy.