The goal is to be free and hopeful in the music. Because that's really the only intention you need. From there, every natural and powerful intention and feeling will, on its own, slide right out of you - out of your spirit.
The main thing that I've learned, artistically, is that if I'm in pain and feeling the budding of anger - if I absolutely feel like I need to write a song about it, I'll either need to transform that anger into something positive, or I'll just need to throw the song away. Because eventually, I'm going to want to transcend that pain and that anger.
To me, what I define as defiance, in some ways, is knowing the "reality" and having the ability to possess a realist mindstate yet still working towards the fantasy and still being childish. While still having the understanding and capacity that would generally inspire pessimism: some sort of more realist perspective that I think most people classify as adult. Anything like that and anything that's sort of fun.
Physical pain is problematic because it's very difficult to transcend that. Sometimes you're just in physical pain, and that's a bummer. Even then, there are beautiful things involved in the healing of that. I've experienced some.