I vote for celery. I realize it's a major component in just about anything I cook, and I never omit it to satisy my taste...but I don't like it. More often than not, I find it bitter, with the exception of the very very tender center, tiny stalks. Those, I love.
Now, if you'd put zucchini on that list, I'd have voted for that, instead. I really have no strong objections to any vegetable.