To some people they don't taste good. Advice for how to self-modify in this respect would perhaps be useful, if you have any.
Sometimes, if you keep eating something regularly for a long time, it starts tasting better. I don't know if it is just a power of habit (familiarity feels pleasant) or whether your brain gradually redefines "food" to mean the things you eat most often (so your desire to eat becomes a desire to eat a set of specific things).
As an experiment, start adding one fresh tomato (cut to pieces) to every meal you eat. (OK, not literally every meal; I wouldn't eat a tomato with a sweet pancake. But if something contains meat, it can contain a tomato, too.)...
I have a strategy for getting myself to eat vegetables. I've been using it for about six months now, and it works well:
Side effect: people who see my plate think I'm a very healthy eater. But sometimes they ask my "why is your salad steaming?"
I also posted this on my blog