My girlfriend didn't really follow football until we started dating. More of a basketball fan, and she hates the Lakers, so that was good enough for me. A couple of weeks back, she admitted that she rooted for the Giants in SB42 simply because they were underdogs and it seemed like Brady already 'had everything'.
I told her that it was a good thing I hadn't known that before, because it would have been a deal-breaker. Still trying to get her to watch the Brady 6. Once she does, no way he won't be her favorite player. He's pretty much the ultimate underdog, no matter how it looks now.