Despite them beating my Dodgers, I'm rooting for the Nats because they seem to be a pretty cool underdog story with likable players. And, being a Dodger fan, while the Cards aren't quite up there with the Giants, I'm inclined to root against StL in most circumstances.
In the AL, I'm no fan of Houston, but there's no way I can root for the Yankees, despite liking Judge. I mean, from my perspective, no fans are as insufferable as Yankee fans, except Laker fans (of which, despite my Dodger allegiance, I am decidedly not one)... Well, of course, you have Raider fans, but that's a whole 'nuther dynamic