Seriously. I prefer to avoid spoilers myself, and it’s not because I’m a superficial idiot who only goes to movies for the plot. It’s because, like any narrative work of art, the way the plot unfolds in a movie is one important element of the story. Just like character, set design, acting, or the score.
Screenwriters talk a lot about “arcs,” and while this is often primarily in the context of character development, the overall plot has an arc as well - one that a good screenwriter can use to effectively build and release tension. One of the tools they use to do that is the element of surprise (or uncertainty). Horror films rely on the unexpected jumping out of the shadows to scare the audience. “Will they or won’t they” pairings on sitcoms derive all of their value from uncertainty. Mysteries center around one big question that, if answered well at the end, will be simultaneously surprising and dramatically satisfying.
Ultimately, nobody’s saying that we’ll NEVER watch something if it’s spoiled for us. I’ve known about Rosebud since I was a six-year old reading old “Peanuts” comics, and I still loved “Citizen Kane” once I actually saw it. But I’m also aware that my experience watching “Citizen Kane” for the first time was ever-so-slightly diminished by the fact that I knew what Rosebud was from the first frame. Rather than driving the narrative of the film via its mystery (and then serving as a final, delicious dollop of irony at the end), as intended by Orson Welles, the Rosebud stuff ends up feeling like an obvious, and somewhat silly, framing device.
A similar example is that of “Saving Private Ryan.” If we as the audience know that the old man at the beginning is the titular private, then the rest of the movie loses a whole lot of tension, because we know the damned kid survives. I won’t dispute that, as a framing device, “Old Man Ryan” is clumsier (not to mention pumped full of Spielbergian sentimentality) than “Rosebud,” but you can’t deny that saving the reveal until the end served an important narrative purpose, even if it wasn’t very well executed.
In other words, plot surprises are one of many elements of good movie-making. Their contribution to overall quality varies from film to film (as noted above, a historical film suffers less from being spoiled than, say, an M. Night. Shyamalamadingdong film - say, 10% reduction in enjoyment vs 75%), but it is almost always something.
As for ** Tim R. Mortiss**… don’t worry, just because some of us can enjoy the emotional thrill of surprise while simultaneously appreciating a film at a deeper level doesn’t make you superficial. Just bad at multi-tasking.