Ask Ira Glass what it's like to be nearing the 500th episode of his beloved public radio show This American Life, and he gives a classic Ira Glass-ian answer.

"Honestly, it feels to me more like an odometer rolling over than anything else," he says before a quick pause of contemplation. "But I think it's because I'm not built very well for self-congratulation."

By any metric, what Glass has done on public radio for the past 17-plus years is impressive. This American Life, his hour-long show of stories centered around a single theme, has employed everything from hard-hitting investigative journalism about the fallout from the 2008 financial crisis to short works of fiction about a duck falling in love with a rock. The show has gone on a multi-city tour, and broadcast live into movie theaters across the country. In 2007 and 2008, Glass produced an Emmy-winning TV version of This American Life for Showtime — and then walked away from it because, as explained on the show's site, "it was too much work doing both the radio and television shows." And last year, Glass co-wrote and produced his first feature film based on a story on This American Life, director Mike Birbiglia's Sleepwalk with Me.

And this Friday, This American Life will broadcast its 500th hour. Its popularity shows no sign of waning with age: Its podcast sits consistently at the top of the iTunes charts, averaging 850,000 downloads a week, on top of its 1.8 million radio listeners.

"It feels like, 'Oh, we're totally solid as a show,'" says Glass, continuing to insist that broadcasting 500 shows isn't a huge deal. "I don't have very bask-y feelings in general about many things, and I feel like maybe if I were psychologically a little better adjusted, I could have that about this, but for whatever reason, I don't. Truthfully, I think if the show weren't going well right now, this'd be a moment where I would be feeling a tremendous amount of nostalgia for the early days of the radio show. But I feel like the last two years or so of the show have been the best, just in terms of the number of good shows and the variety of things we've done and the ambition of things we've done. I don't feel myself looking back very often. Including now, when it would be appropriate to."

That said, Glass was nonetheless game to look back on some of the episodes that stand out in his mind as particularly meaningful or memorable to him, for better or, perhaps, for worse. "As I've gone into this process of thinking about the shows that I feel the most attached to," he says, "I wish that I weren't this sort of person, but I think I am, where the ones that I feel the most strongly about are ones I have some strong personal connection to" — including the very first episode, broadcast on Nov. 17, 1995.