One I was tempted to walk out of until I "got it" was Zardoz with Sean Connery. It's a farce, but you have to remember the opening credits to make sense of it.

Another one I almost walked out of was Rollerball. Again, by sticking around it made a lot of sense.

I should have walked out of A Walk in the Clouds. Stupidest damn premise and most idiotic ending of a story, with (if I remember correctly) a bunch of Mexican-American actors portraying second-generation Italians in the California wine region.

SRS