Everyone knows at least one person who does it. You mention that you're about to watch a new movie. Before you can finish your sentence, they say, "Oh, wait until you see the ending." Or perhaps you're halfway through a bestselling novel when someone casually reveals a major plot twist. To many people, spoilers feel like a social crime. They can reduce suspense, ruin surprises and trigger instant frustration. However, psychology suggests that people who constantly give spoilers are not always trying to be annoying. In many cases, their brains may be responding to powerful psychological forces involving excitement, social connection, status and self-expression.
The behavior may have less to do with ruining stories and more to do with how humans process information and share experiences.