As a regular listener to the show for roughly a decade, I was almost certainly part of the target audience for this past weekend’s episode of This American Life. The show was created and is hosted by Ira Glass, and each week he introduces the episode’s weekly theme, drawing you in with a very practiced naturalism. At its best, the show fools you into feeling like you’ve just had the best conversation of your life, and you didn’t even say a word. Here’s Glass in an interview:

I mean radio is a direct and—how do I say this?—radio is like a machine for empathy and intimacy, in a way that is hard for almost every other mass medium to recreate. Like, radio is closer to a Tumblr, or a blog, or Twitter, than it is to television, I think. There is a feeling, when you listen to radio, that it’s one person, and they’re talking to you, and you really feel their presence as one person.

He’s right. The feeling of intimacy that Glass and the This American Life producers manage to create with their show establishes a relationship with its audience that is qualitatively different from what one experiences with, say, a TV show. As a result, I tend to listen to This American Life less critically.

This particular episode, though, had a twist: Fred Armisen co-hosted it—in character as Ira Glass. I’m a fan of both men. I’ve read Glass’s “manifesto” more times than it’s cool to admit, and Armisen’s Portlandia, probably the only sketch show with a thesis statement, hits me where I live. But when the format for this episode was announced last week, it filled me with dread. Will This American Life finally get too cutesy even for me?

The episode was called “Doppelgangers.” Fred Armisen, we learned, first did his Ira Glass impersonation in a dress rehearsal for Saturday Night Live two years ago, but the segment didn’t make the air because, according to Armisen, Glass isn’t famous enough to impersonate on national television. This American Life itself is, as Glass said in introducing the show, “the one place where I actually am famous enough to use this imitation.” Except when Armisen showed up, something felt a little off. I wasn’t alone in the room with the show anymore.

Intimacy is tough to engineer—it’s no small feat that Glass & Co. have succeeded in doing so for years now, even as the show’s audience has expanded and the conversational style of This American Life has become increasingly common on public radio. But as the show becomes more popular and especially as Glass’s star continues to rise, reproducing that sense of intimacy gets even trickier. Armisen’s appearance on TAL felt like nothing so much as an attempt to understand how Glass’s fame does and doesn’t affect that intimacy. And the unwitting lesson of it was this: Just because Glass is famous enough now to have an SNL cast member do an impression of him doesn’t mean that impression belongs on This American Life.

It’s been a weird year for the show. Its biggest episode ever aired at the beginning of last January, the now-retracted story of Mike Daisey at Foxconn. The episode devoted to retracting that story, which aired in March, has since become one of my all-time favorites. Long-time contributor David Rakoff gave his last TAL performance at a live show in May (“The Invisible Made Visible”), not long before he died. He danced. It was heartbreaking and beautiful. Then in November the show aired a rather odd story about Ira Glass’s dog. 

And now there’s this episode. Not that they were trying to fool anyone, but Armisen was easy to distinguish from Glass; the latter’s voice, despite what you may be hearing in your head, was noticeably deeper than Armisen’s version. The impersonation changed as the show went on—it sounded as though Armisen was trying to deepen his reedy version of Ira’s voice to better match the real thing. Neither said anything about this. Maybe they were having too much fun to notice. As a listener, though, having Armisen in the room inevitably made the whole exercise weirdly self-conscious. “I feel like a muppet,” Glass said at one point. “Why does it make me feel like a muppet, Fred?”

Granted, if you listen to the whole episode, Armisen’s impersonation may not strike you as the most important thing about it. The first story in the show (“Act One,” as they always call it) asked whether restaurants are passing off pig rectums as calamari, which is a difficult question to un-hear. The second story—there were two acts this week—juxtaposed interviews with a soldier who served in Afghanistan and someone who grew up in bad Philadelphia neighborhoods. It was about PTSD, and trauma more generally. It was riveting.

But whenever we heard Armisen in the booth the distance between the show and its listeners—this listener, anyway—grew. Fortunately, there’s no reason to think he’ll be back. It was probably a one-off thing. But it highlighted a real problem for the show, one that may not go away soon: As Ira Glass becomes Ira Glass, will his fame and public persona create a gulf between the show and its listeners that makes the kind of intimacy it has been so good at establishing impossible? In fact, the little experiment called such awkward attention to that problem I began to wonder why they decided to go ahead with this goofy stunt on a show that is so admirably careful about its tone.

And then they plugged Portlandia.