Cookout pasta salad. I like pasta, mayo, corn, tomatoes, cucumber, olives, onions, whatever else goes in normally, but pasta salad is just so disappointing.
I am the opposite about a Reuben- I’m not especially a fan of pastrami, sauerkraut, Swiss cheese, or thousand island dressing, but fuck if it’s not incredible together.
I like your idea of reversing the question. On their own I'm not big on sour cream or mayonnaise, but either of them mixed together with the right seasonings or sometimes even together with some seasoning and I can't get enough. Mayo is nasty, but a garlic aioli? Fricken great. Plain sour cream? A tad on a baked potato is fine, but a chipotle lime crema? I might lick that up off the floor...