A New York sports opportunist will therefore choose to be a fan of whichever team is currently doing better in each sport. They will then act like they've always been a fan of that team, and vehemently deny ever liking another team in the same sport.
It's important to note that not ALL residents of the New York area are New York sports opportunists, but there are vast numbers of people that are.
REALIST: No you haven't. You wore a Mets hat all through the 80s, and the first half of the 90s. Then suddenly you became a Yankees fan. That makes you a New York sports opportunist.
NYSO: No way, you're just jealous because my team rules!
NYSO: Woohoo! My Giants just ended the Patriots perfect season!
REALIST: Yeah, you weren't a Giants fan until a few weeks ago. I bet you can't even name five players on the team.
NYSO: Well... there's Eli Manning, and... uh....
NYSO: Well, the Nets aren't exactly great, but I'm so glad I like them instead of the Knicks, they really suck!
REALIST: Why do you have a listing on ebay for that autographed Patrick Ewing poster that used to be on your wall for so many years?
NYSO: I have no idea what you're talking about.
NYSO: I love the Devils, but I also bought a bunch of Rangers and Islanders merchandise and buried it in my closet. You know, just in case they ever get good again.
REALIST: Stop the presses.