The scum of America. Whenever the Yankees lose, they bring up their 27 world series rings, as if that means anything during that game. Yankee fans are most hated by Red Sox and Mets fans, but the fans of the other 27 MLB teams hate them too. They like to start fights with anyone that they think is a Yankee hater. Unlike most fanbases, who usually only boo their own team/players when they fuck up royally, Yankees fans will boo whenever someone fucks up, even if it's just a small fuck up. They are also some of the most uncivilized people on Earth.
example A: Someone with New York license plates and/or anything pro-Yankees on their car parks outside of Fenway Park. The car is usually left alone. The owner of the car walks into Fenway Park all decked out in Yankees gear. He or she is shouted at, booed, and heckled by RedSox fans.
Example B: Someone with Massachusetts license plates and/or anything pro RedSox parks their car outside Yankee Stadium. They will most likely return to find their tires slashed. The owner of the car goes into Yankee Stadium all decked out in RedSox gear. He or she is shouted at, booed, and heckled, and more often than not they are also pelted with anything that can be thrown at them by Yankees fans.