My vegetarianism originated with a concern for animals. I had believed that meat came from animals that had died natural deaths. I was four. I also believed that God lived on a cloud, like the CareBears, although, clearly on a different cloud. My parents went vegetarian with me. My father is currently veggie, my mom isn't.
I still believe that animals should be treated with respect, but I'm not an aggressive animal rights advocate by any means. I think that animal testing has it's place. (Medicine, yes. Cosmetics, no.) I don't think that there's anything inherently wrong with eating meat, but I do think that eating meat and refusing to think about where it comes from is irresponsible.
I believe that being vegetarian lightens the toll I take on the earth a little, just like car-sharing and recycling. I believe that walking gently over the earth is good stewardship, and vegetarianism is something that I can do. I'd like to compost. I'd like to eat a more organic/local/fair-trade/free-range diet. I'd like to do a lot of things I'm not ready to do yet.
Being vegetarian isn't a huge part of my identity, or even my daily life. It doesn't take up a lot of my thoughts. I think about food often, but I rarely think about not-eating-meat. It's certainly not a large part of my faith. My food choices are often a bigger deal to other people than they are to me.
But being a vegetarian is a mindful step that I made towards God. Each change that I make in the way I live my daily life is a change I make in order to be closer to the person He wants me to be. I've got far too low a self-esteem to fully buy into the Quaker idea of perfection, but I am always striving to be a little bit better. And right now, for me, that means not eating meat and not passing judgement on those who do.