I'm not a baseball fan, but my husband and sons are fans. They cheer for the Cleveland Indians, which, as a general rule, gets harder and harder to do by the end of the season. They don't like Detroit and always root for whatever team is playing against them...EXCEPT when Detroit plays against the Yankees. Then they root for Detroit because as they say, "Everybody hates the Yankees." HA! :-)
I love baseball and have been a St. Louis Cardinals and Atlanta Braves fan since childhood. (They were the only two teams I've ever lived close enough to see play.) I remember cheering once because the Yankees beat some team we didn't like. My dad turned to me and said, "Don't do that. We don't ever cheer for the Yankees." To this day I have no idea why!