Actually, just to be a minor stick in the mud, I don't actually find Rodney quoting Buffy all that much of a stretch because in addition to being a man in his late 30s, he also such a total GEEK. And since Buffy is a such a "cult TV" icon, as much as a pop culture icon, I can see Rodney knowing a reasonable amount about the subject.

Sure, I'd expect him to know more about Dr Who and Batman, even the X-Files, but I just don't see Buffy being out of his range.

But Rodney quoting Gilmore Girls or The OC would throw me utterly.