For me its Batman Forever.
Despite what alot of fandom tends to think, Batman Forever was a popular film with the GA when it was released, and no , the general audience of 1995 wasn't bitterly disappointed with it.
It was very much a 90s action popcorn flick , and at that time, general audiences weren't looking for a Nolan or Snyder style take on Batman.
The critics weren't kind to be sure, but the film was a major success, and was popular with audiences.
Audiences cheered , laughed , and clapped each time I saw BF in the summer of 1995.
BvS was the opposite result .
When I saw BvS 20 years later in a packed audience, the audience was silent through the whole thing, and walked out of the theater befuddled, with zero applause through the whole thing.