If you cower in front of those trying to make/keep you small, they have won. That sentiment is very helpful to me.
Also: What, are you emo now? helps me to realise that I'm cowering and helps me to pull myself together.
In terms of quotes of other people, there's 'my' fight song, Welcome to the Black Parade by MCR
Do or die, you'll never make me, because the world will never take my heart - You know, an existencialistic atheistic world view is not the best prerequisite to feel like there's any point in anything at all, so I stand up against reality to keep it from breaking me. Just because. Take that, reality!
I'm not afraid, I'm gonna show my scar - Quite literally, since I don't hide the scars on my arms and legs. But more importantly, I will not feel ashamed because I am mentally ill. I will not feel like a lesser human being. I will stand up for my rights as a nutcase. I will not beat myself up for the things I can't do. I will not succumb to other people's ideas of how I should heal or whom I should heal to be.