Since Nathan Fillion is playing the LAPD’s oldest newbie cop in ABC’s fall drama The Rookie, he’s the butt of a lot of geezer jokes. And he’s fine with that. “It’s really hard to make people laugh,” he told Michael Ausiello during a visit to TVLine’s San Diego Comic-Con video suite Saturday. “It’s very easy to let people to laugh at you.”

Besides, the Castle vet isn’t hung up on age, at least not anymore. “I actually had a bit of an epiphany this weekend — a total flip,” he said. “I can list off 20 mistakes I can see everybody making that I won’t make anymore because I’ve lived through this, guys. I can tell you how that’s gonna end. I have wisdom.”

Fillion also has his work cut out for him in trying to make The Rookie as big a hit as Castle was, especially since the former’s John Nolan is so different from the latter’s Rick Castle. But divorcé John’s situation “is the new cultural norm,” he suggested. “When I was growing up, I feel like people stayed married. Now, divorce is the norm, and men my age… their life changes entirely. They’re no longer needed as a father figure [or] a breadwinner… careers sometimes halt, and they’re left without a job to do. So men start over.”

Also included in the Q&A are Fillion’s reactions to seeing Con-goers dressed as characters from Dr. Horrible’s Sing-Along Blog and his explanation for how he wound up spoofing Firefly on American Housewife. Press PLAY on the video above to see all that — plus the moment he turned the tables on his interviewer — then hit the comments. Do you think you’ll be able to love John as much as you did Rick?