When I saw Bo Derek's "Tarzan and Jane" back in the 80's, I walked out about 1/3 of the way through along with most of the rest of the audience (after they had been yelling insults at the performances and throwing food at the screen).
My sister-in-law insisted I watch "Mama Mia," but after the first 10 minutes of a bunch of girls giggling while running on the beach together, I bailed.
Bo Derek's 'Tarzan and the Apeman' was the first movie I went to that people sat through the credits thanks to her frolicking around in the surf naked while they rolled.