I am not overly fond of red meat, and when I was a child I hated any kind of flesh. Fish was okay, but I was intolerant of red meat and white meat or eggs (blargh!), which left me eating a largely vegetarian diet, and it was easier to just introduce myself to people as a vegetarian (even though I wasn't), rather than go through a list of things I would and wouldn't be happy to eat.
These days I can stomach a bit of red meat occasionally but to be honest I still don't like it. The taste of it makes me think of the pain I got from eating it when I was younger, and I just don't think it tastes nice at all unless heavily disguised with herbs and other flavours. I still can't stand eggs looking or tasting like eggs; I have an aversion to them to rival Hitch****'s. But I eat a LOT of fresh fish. And chicken. A few times a week on average. I could be happily vegan as long as I could make food that wasn't boring and had the ingredients available to do it. I would have to take iron and calcium and other general supplements though, as I've discovered my body needs a lot of both of those.
I have a vegan friend who says his diet is amazing for staying willow-thin. I'd do it for my own general health - but instead I'm trying the 'eat once a day' thing instead for now. I'm sure I'll give it a go someday.