My partner and I definitely do this. The current example that occurs the most is when we're watching Late Show with Stephen Colbert, and we speculate about whether the writers regret having him do something (because chances are he's been doing it ALL DAY and annoying everyone) or whether they are having a good laugh at getting him to do something (like eat awful food).

But we used to speculate about this with Buffy a good deal, probably because that was the only show where we had a good idea of who the writers were.

And there are other times, either generically ("What were they thinking?") or specifically ("Do they really think people are interested in X?") when we're thinking about plot choices AS plot choices rather than developments in a verse.