There's a story that there was a special advance screening of the 1997 'Batman & Robin' film for the DC Batman staff at the time and at the point where Batman pulls out his Bat Credit Card the comicbook editor let out a SHRIEK of horror.
(My recollection of the story might be a little hazy.)
I've heard that Mario Puzo spent much of his time at the premiere of Superman: The Movie quietly saying "I didn't write that!" When Superman travels back in time at the end, he said it loudly enough that many in the cinema heard him. Now that commentary would, IMHO, definitely have improved the movie.