Books

Yes because there is no point in finishing if you don't have the surprise.

Yes, it does. It is part of the fun.

For me specifically, if spoilers hurt a book, it probably wasn't worth reading in the first place. I love when authors demonstrate mastery of language and narration, and no amount of spoilers can overshadow the direct experience of witnessing it enacted.

If I'm into the story, yes. Feel like this kind of question doesn't understand that a lot of stories only have going for them resolving one or two questions. Once you know the answer the rest of the story is so average it's hard to care to finish. For example I read a lot of otome isekai (tl;dr romance novels where the heroine was sucked into a novel/game). Once you know the twist it's just a subpar story.

That said if a story is kind of shitty and I'm considering dropping it, but I read a spoiler the twist is actually really good and puts the crappy parts in an interesting context I'll keep reading. So case by case, reader by reader basis. I have stories I only finished because I read a spoiler, but I have just as many I never finished because I read a spoiler.

Depends but for the most part it does for me. Like one user said the suspense is ruined so then I become less invested in the details between point a and b.

Yes, absolutely. I can enjoy second reads, but discovery can be an important part of the journey. Will I get as invested in character A if I know in advance they're going to get killed off? If I don't get as invested, doesn't that lessen the emotional impact and thereby diminish the story?

Someone mentioned that we all know how The Titanic ends. But the fate of the Titanic was never more than a plot device, and the ship wasn't the focus of the story.

I was lucky to have been utterly ignorant about Sixth Sense - I hadn't even heard there was a twist ending, so I wasn't looking for one, and the ending was consequently both a surprise and so much more impactful than if I'd known how it ended.

I remember seeing a study in which most people expressed a dislike for spoilers—but when groups watched films (or read books—I forget which) with and without being given spoilers, the reported enjoyment of the groups that had been given spoilers was higher.

I believe they do. Even if I have a hunch about where the story might be heading, I prefer to preserve the suspense and experience each twist and turn as it was intended by the author. Spoilers can diminish that sense of discovery and surprise, which are central to the enjoyment of any story.

Not really. Dramatic irony exists for a reason.

https://www.britannica.com/art/dramatic-irony

So, for example, Titanic. We all KNOW what's going to happen. The question then becomes how the characters deal with it.

Yes

I find it does. Part of the enjoyable tension of a book is not knowing what comes next, and the satisfaction of a plotline well-executed.