I’m a walking bag of contradictions. In my mind’s eye, I am free of bigotry, but as soon as someone I don’t know walks in the room, I immediately start sizing up the music they listen to, based upon their appearance and wardrobe alone. Typically, the set of associations goes something like this:

Ann Taylor pantsuit: Natalie Merchant
Polo shirt, khakis, possible African choker: Vampire Weekend
Tie-dye T-shirt, jeans, over 35: Dead, Phish
Tie dye T-shirt, under 35: Fleet Foxes
Business suit, two ties: Wazmo Nariz (to get that one, it helps if you were in Chicago around 1980)

Too often, my stereotypical associations turn out to be, well, right on the money. That’s what made it gratifying to learn last month that I was dead wrong about the musical inclinations of America’s left-leaning sweetheart, MSNBC pundit Rachel Maddow. I would have suspected her to favor the gentle and droll—some Belle and Sebastian here, some Jens Lekman there. Judging from the glasses she sometimes wears in interviews, perhaps some Buddy Holly or Elvis Costello would enter the mix.

But metal? That would bring back memories of the epic Terry Gross/ Gene Simmons smackdown from a few years ago. I would have judged mild-mannered Maddow more likely to be a pastor of muppets than a master of puppets (and yes, she has drawn a muppet analogy to the decline of the American auto industry). Yet before an interview with Metallica’s Lars Ulrich, the Rhodes scholar blushingly described herself as a “fangirl.” Maddow displayed the “Enter Sandman” ring tone on her Blackberry and described how the Master of Puppets album changed her life when she was fifteen. And the fan-love went both ways; in a recent Time feature, Ulrich put the Rachel Maddow Show on the short list of his favorite things, right up there with tightrope artist Philippe Petit and Mark Rothko, who loved black even more than the average Metallica fan.

I’m by no stretch a metalhead; to me, Howlin’ Wolf makes James Hetfield sound like a girlyman. But I appreciated Maddow’s explanation of how Master of Puppets’ cathartic rush became the soundtrack to everything she wasn’t expected or supposed to do as a teenager. And Ulrich did his part to mess with my stereotype of the heavy metal drummer, which essentially comes from the Spinal Tap theory that they’re interchangeable and likely to spontaneously explode (“Most of them died in their sleep while playing,” explained Tap’s David St. Hubbins.) On the show, Ulrich, the diminutive Dane and Michael Keaton lookalike, chatted up the virtues of social democracy and San Francisco tolerance. When Rachel asked Lars his reaction to Metallica’s music being used to harass prisoners during the Iraq War, he shrugged it off: “I could name 30 Norwegian death metal bands who make Metallica sound like Simon and Garfunkel.”

Rachel Maddow interviews Metallica’s Lars Ulrich

Wilco, “Heavy Metal Drummer”