Anything that says lamb/sheep on the label. If I don't know it is in the food, OK, but I gag when I discover it is in the food. Courtesy of my mom telling us it was unfit for humans to eat. Bubble and squeak (boil potatoes until they dissolve, add cabbage and continue to boil til it is no longer recognizable and add poor cuts of beef and continue to boil until it too dissolves. You can fry leftover from it the next day. It was bad the first time, it was worse the second time.
Any meat with milk dish - that is just plain wrong. (Cheeseburgers excepted).
Best meals, red cabbage saluted with vinegar, cabbage rolls, smelt fish (Actually, any fish), pork chops with mountains of fresh horseradish.