I'm surprised nobody has mentioned vitamin B12 yet. Yes, I know there are vegan sources, but they are all "unnatural" - fortified supplements.

As far as "it's easy to be a vegan" goes, I don't think it is. I don't eat a lot of meat - maybe once a month or so when I go to someone's barbeque or something. I was vegetarian for a year or so, but that was due to health rather than moral reasons. I found it hard socially, and I live in a wannabe hippy university town - I can't imagine how hard it must be in the southern states, for example. By "hard socially", I mean that I didn't want to be the "fussy eater". Dinner with my grandmother, for example - she would be offended if I didn't eat her pork. Ordering a pizza with friends, I don't want to be the person to insist on a veggie option.

I also don't think that meat-eaters are threatened by vegans, only by evangelical vegans. There's this food chain thing where animals eat other animals, so I don't think it's inherently wrong or immoral to eat animals, although I do think that most people eat altogether too much meat. I also don't think it's healthier to be vegetarian - from my experience, I have more energy when I'm eating meat once in a while rather than not at all.