For most of my life, I didn't like vegetables. My mom said that when I was very young, I loved peas and carrots so much that she would add more of them to my soup. She said I began to reject vegetables when I began watching Sesame Street and got exposed to the idea that kids don't like vegetables, but adults push kids to eat them because they're healthy. Somewhere inside, I still feel this way - if someone is pushing me to do something because it's good for me, I figure it must not be something that I would want to do on my own. It's hard to like vegetables in a culture where "Eat your vegetables" means do what you're supposed to do before you can get what you really want.
I have a much better understanding of what I like and don't like based on the actual flavors of the food, not what other people tell me I should and shouldn't eat. If you experience things like food holistically (like I do), it can be hard to make that distinction, but trying different foods will help you figure it out. With all the unwanted pressure to go on diets and care about calories, there are still times when I want to reject all vegetables. But I can't. Because guacamole is still at the top of my list.