Two come to mind, actually. One was at a Chuckie Cheese in Troy, NY, tasted like tomato soup and Kraft parmesan cheese out of the jar. OMG, it was totally inedible.
Then, comes to mind, a Pizza Hut creation in Tecumcari, New Mexico, several years ago. We were making our way home from Colorado. Spent the night there, and in the motel was a little sign on the table in the room. The kids just wanted to swim and pizza was fine for supper so against out better judgement we went to the Pizza Hut. Horrible. And the waitress was cleaning off tables by rolling a garbage can through the dining area, scraping the leftovers into one side and the stacking the dishes into the other side of the garbage can. Never saw that before, or since! I couldn't help but wonder what my health department guy would say.