I attended last night's Mets-Phils game with my roommate and his girlfriend, both of whom are Phillies fans. Well, the girlfriend didn't care who won so much, but she rooted for the Phillies because she "didn't want to argue with her boyfriend" or "get left behind at the stadium." Lame. Anyway, my roommate told me before the game that he couldn't believe how intense the Mets-Phillies rivalry had gotten. I disagreed. I felt that while the Phillies were trying to create a rivalry, the Braves still concerned Mets fans way more than the Phillies did. No one was mad at the Phillies for winning the division last year - we were pissed at the Mets for blowing what should have been an insurmountable lead.
I couldn't have been more wrong. The atmosphere at Shea was intense, to say the least. A bunch of my good friends from college are Phillies or Mets fans, so over the last few years we've often gone to Mets-Phillies games at Shea together. In previous years the Phillies fans heard a comment or two, but for the most part people left them alone. Not this year. Our entire section (Loge reserved behind the plate) booed my roommate every time he got up or sat down since he was decked out in Phillies gear, and by the 7th or 8th inning I even found myself leading the chorus. The section also booed and hollered at any other Phils fan who walked by, and there were numerous "Phillies suck!" chants, especially as everyone filed out of the stadium at the end. Some people crossed the line too. One Mets fan dumped beer on top of a Phillies fan, and the usher even tossed a few guys in yarmulkes for causing a scene.
So I guess there's a real rivalry now. We'll see what happens after this, but I expect tensions between the teams and the fans to escalate as the season progresses.