The mess hall at 29 Palms, CA is where I have had two regretfully unforgettable meals. I can choke down liver that is prepared properly, with lots of onions. But the stuff they "cooked" there had the consistency and appearance of a dusty boot sole. I'm betting the boot sole tastes better. It did teach me to get to the mess hall within the first hour of it opening, though.
The other bad one was the first time I ate greens. Being a pasty yankee, I had not had the opportunity to eat greens (collards, turnip, or any other), but had wanted to try them. Although they called it greens, which was their right as it was the proper color, it was nasty. It tasted like someone had emptied the lawn bag into a vat of boiling water. I was positive from that point on that the southern boys were absolute morons for raving about greens.
It took about seven years for me to try them again. This time a friends mother-in-law prepared them. They were the shiznit! Southern cuisine regained loads of esteem at that meal.