BIG veg. We had a close friend who retired, bought a farm and grew superb vegetables, but he never harvested them in their youth. Huge zucchini, enormous green beans, gigantic radicchio. He complained that he didn't understand the radicchio craze because he found it bitter and inedible. Well, yes, when it is 8 niche across and 6 inches tall! And 10 inch long, fat and coarse green beans. And of course the practical joke baseball bat zucchini.
Sure, the baby vegetable trend was overdone, but small sweet and tender vegetables often make converts of the worst veg hater.
I really can't think of a horrible vegetable, since there is a way to.make every food delicious. No bad food, just bad cooks. Come culture somewhere has a palatable recipe.