There are very few foods for which I have an irrational hatred. In fact, there really might only be two, and they are squash and cilantro. I find the former to be an exceedingly bland food, and for some reason, that kind of grosses me out. I tend to avoid it in all situations. With cilantro, I actually have a very unpleasant reaction to the smell of it, especially while chewing it. It's similar to when I eat too much horseradish, but whereas I actually enjoy the taste and sinus clearing power of horseradish, cilantro overwhelms me with the sensation of taking a deep breath a dirty locker room. I find that enough of it can completely ruin a meal for me. Not even squash can do that. I've read that it's actually a genetic thing, and that some freaky people just have that sort of reaction to cilantro. I guess I'm one of them, so maybe this one isn't that irrational. It doesn't help that it seems to be in everything these days.
Anyway, I say "irrational", because I've found that most things that I thought I disliked over the years are only as a result of never having the dish or ingredient prepared properly or even well. As I've gotten a little older, I've learned to put myself in the hands of the chef and to let him or her do what they do. These days, I just order whatever looks most awesome on the menu, regardless of the ingredients and my preconceived notions of them. I'm willing to have the kitchen prove me wrong, and more often than not, they do just that. I don't know if that makes me "adventurous"; I think it just makes me more open-minded than I used to be.