Actually, Buffy is surprisingly bad for this. Think about it: most of the time when Buffy is talking to Willow, they're talking about Angel. Or Xander. "Work" discussions are usually held in co-ed groups. Anya: only talks to the other girls, alone, about Xander. Dawn/Buffy convos might pass, but that's in a completely different context (familial.)

Hell, even a show like Bones fails this in situations where it shouldn't. Female boss has three subordinates, two male, one female. 90% of her solo conversations with male subordinates: work-related. 90% of conversations with female subordinate: about men, even though they have exactly as much narrative and situational reason to be talking about work.