Well ... I'm on those very rare "NY" baseball fans.
I have an abnormal ability to root for both the Yankees and the Mets.
Until recently - it was never an issue since they never played against each other except for an annual charity game (Mayor's Trophy). The thought of a Subway Series wasn't even close to being an option. When 1 team was good the other stunk.
If I had to pick one it would probably be the Yankees. But I had Mets season tickets at one time too. Go figure.
My Grandfather was a NY Giants fan - when they moved to San Francisco there was no way he was rooting for the Yankees - so he was a Met influence. My older brother and his friends made me swear to be a Yankee fan or they wouldn't take me to a game ... My Dad ... more Yankees than Mets but would watch either. So there was no strong influence one way or another so I rooted for both as a kid. Today I just enjoy the game. Although I stayed away for a long time after the strike.
I'm not like that with other sports. In other sports it's Rangers (Hockey), Knicks (Basketball) and the GIANTS (football ... with a little rooting for the Miami Dolphins).
What can I say ... rare ... like an HCS or GT/CS
... there are very few of us around.