Rivalries are perhaps the superfine ingredient that works to spice up teams and athletes and make fans louder.
Think of the New York Yankees and Boston Red Sox in the major leagues, the Pittsburgh Steelers and Baltimore Ravens in the NFL, Real Madrid and Barcelona in soccer. Or in the old days the Los Angeles Lakers and Boston Celtics. Or in the Olympics, matchups between the U.S. and Soviet Union always had their own special flavor.
And in the World Baseball Classic, games between Japan and South Korea have always created the most intense atmosphere because of the two nations' past history (although there was no game between the two in this year's tournament, as South Korea was eliminated in the first round).