FC Den Bosch, the club I grew up with - as I am from the area. First club I ever followed, first club I ever saw play live, first pro player I met on the pitch was from there... And the club I vowed never to set foot in the stadium again, after the most dire game I ever saw: FC Den Bosch - Excelsior, 648 paying spectators in a 20.000 seater stadium.
Oh, the chances of them ever coming up against Man Utd are virtually non-existant. If it would happen, though, I’d root for the underdog and for nostalgia.
Some other teams I do have a soft spot for (because I lived there), like Union Berlin or Schalke. From some of the other cities where I lived I somewhat dislike the clubs, like FC Köln, or FC Basel, or Ajax. The last one could be down to living in Rotterdam atm.