The Mask (1994)
The Prestige (2006)
Major spoilers after the trailers.
For the record: I don't care that much about spoilers. That's not to say that I will seek out information on how a story ends, if I plan to enjoy it myself later; but I won't object if you want to tell me what happens in a particular narrative for the purpose of discussing it further. In general, I agree with Scalzi's Spoiler Statute of Limitations, and I do my best to check with any audience or conversation circle before dropping spoilers.
A big part of this is that it's just plain difficult to avoid spoilers these days. Marketers and promoters seem to want to reveal more and more about their products all the time, to the point where I've literally seen a three-minute movie trailer and then felt no need to see the actual two-hour film, because I was pretty sure I knew everything important that was going to happen. Part of that is how formulaic some genres can be, but studios also want to reassure audiences about what to expect when they sit down in a theatre. And nobody can agree on how potentially damaging spoilers actually are.
You may recall seeing news articles like this one about a 2011 UC San Diego study on the psychology of spoilers, which trumpeted the conclusion that "Story Spoilers Don't Spoil Stories" (PDF). However! A more in-depth 2014 study titled "Spoiler Alert: Consequences of Narrative Spoilers for Dimensions of Enjoyment, Appreciation, and Transportation" (PDF), came to the exact opposite conclusion, reaffirming the conventional wisdom that spoilers can and do adversely affect an audience's enjoyment of a story:
[A]lthough spoilers may not always "spoil" as much as one is intuitively led to believe, they can certainly harm the audience's experience, or at least specific facets of their responses to the narrative. The present results demonstrate that spoilers do not have a universally positive effect on enjoyment and related media gratifications... Clearly, for some audiences, the production and editing of trailers and promotional materials should aim to minimize spoiling narratives, while programmers who write code that helps fan communities avoid online spoilers (Liebelson, 2013; Nakamura & Komatsu, 2012) are likely providing a useful service.Scholarship on this topic is still pretty thin, with only a handful of studies to date. And there's an overwhelming tide of lay opinion which probably makes research difficult, from Joss Whedon calling surprise a "holy emotion" to Mark Evanier's friend Bob learning that Richard Dreyfuss is an alien. We instinctively want our first experience of a narrative to be completely fresh—perhaps because that's how real life works—and we each know how much story spoilage we ourselves will tolerate.
There are many fun things in both The Mask and The Prestige besides their respective "twists," but they hold up to repeat viewings for two reasons, I think: one, because knowing what's coming allows you to appreciate the build-up to that reveal, hints and misdirects both; and two, because the point of each story is not just surprising the audience, but surprising the characters. We care about how the people in the story deal with the revelations, and knowing what's coming gives you a clear before-and-after view.
Finally, director M. Night Shyamalan demonstrates the proper way to pronounce the title of this blog post: