I'm a die hard Mets fan here, I don't think there's more passionate die hard fans than Mets, Yankees, Phillies, and Red Sox fans. I've been to a lot of MLB ballparks all over the country and there's no place like the Northeast when it comes to baseball!
There is ONE place you forgot, CHICAGO!! My Great Uncle's wife is from Chicago and when the Bears played the Giants (or it could've been NY baseball against Chi I don't remember) They had to watch the game in DIFFERENT rooms because they would argue and fight. No joke.
