Brock and Roman.
Going into WrestleMania 31, I wasn't looking forward to their match. I thought Roman was being pushed too soon and Brock wouldn't be able to carry him. And the buildup did them no favors either. But their match was fantastic. Even before Seth came in, they had way better chemistry than I thought they would have. It was the last classic WrestleMania main event.
Then when it was time for 34, I was 50/50. The buildup was trash, but I was optimistic that the match would make up for it. And it ended up being the kind of match I was afraid of them having at 31. An embarrassing main event where the wrong guy won. And every match they had after that was just as bad. Trading finishers back and forth like Pokémon cards. fukk that.