Taking away the element of surprise seems like it should make a story less enjoyable. Yet people will watch movies with surprise endings more than once, and people still gladly watch classics like Romeo and Juliet even though they know the story.
UC San Diego psychology professor Nicholas Christenfeld put spoilers to the test. Not only do spoilers not earn their name, they should really be called "enhancers": people consistently enjoyed spoiled stories more than unspoiled stories in experiments.
We spoiled the result, but wait, there's more to Nicholas Christenfeld's research on spoilers and why they help us enjoy stories: