I know this sounds weird, but I'm a life-long fan of two different NFL teams. I grew up in Central New Jersey, halfway between New York and Philadelphia, and as a result never felt any natural tie to any teams from either city. Instead, I adopted the teams from my parents' respective hometowns: Initially that was the Lions (my first memories are of Billy Sims' rookie year, although it might have started earlier). Meanwhile, a couple years after I started following the Lions, Washington hired Joe Gibbs and he won a Super Bowl, solidifying my relationship with that team as well (Interestingly enough, while I cheer for all of the other Detroit sports teams, I feel zero loyalty to the Nats, Wizards or Caps).
I recognize that it's kind of weird to have two favorite teams, especially when I'm not from either city, but it's pretty much all I've ever known. The other thing that's interesting is that, while the Lions often exasperate me, their haplessness endears them to me even more. I don't have the same emotional attachment to my favorite sports teams as I did when I was a kid -- when Larry Bird stole the ball from Isiah Thomas in the '87 conference finals, I was inconsolable for days -- but I know that if/when the Lions win a Super Bowl, the joy I feel will be thoroughly earned.
With Washington, it's a bit more complicated. I hate the nickname, hate the owner, have been disgusted with just about everything they've done over the past two decades. It really is just inertia at this point. And yet, despite the fact that I could easily downshift to only cheering for one team like a normal person, I can't imagine giving them up.
Oh, and in case anyone is wondering, when Washington and Detroit played each other in the 1991 NFC Championship Game, I was wholeheartedly cheering for the Lions to make their first Super Bowl, even as I knew they had no chance.