Which story is about ordinary people doing something horrible to their neighbor?

The story you're referring to is likely "The Lottery" by Shirley Jackson. In this unsettling tale, a small town conducts an annual lottery where the "winner" is stoned to death by the community, including friends and family. This chilling narrative explores themes of conformity, tradition, and the capacity for ordinary people to commit horrific acts against one of their own. The story serves as a powerful critique of blindly following societal norms without questioning their morality.