The New York Yankees versus the Boston Red Sox; the Los Angeles Lakers versus the Boston Celtics; the Dallas Cowboys versus everybody. Rivalries have been a quintessential part of sports fandom since its inception. Fans despise a rival team just as much as—if not more—than they love their home team. The science behind why that antagonistic nature in sports exists can also help explain the variation in disappointment in the aftermath of the 2024 presidential election.