Downton Eye Rolling

I'm not a British historian and if you asked me what time period Downton Abbey takes place, I would have to guess--like, I know it's post-WW I, the beginning of the Charleston, flapper era. I would never say that it's still Victorian times (is it?), so, clearly, I cannot be trusted to notice anachronistic details, but I'm just wondering, when did eye rolling as a response come into vogue? If this was a freshman rhetorical essay, the answer would be, "Since the beginning of time, eye rolling has been one way of expressing sarcasm and dismay." But it seemed that everyone in last night's episode was responding with the eye roll, well, truly, the cook, mostly. Daisy is too naive and stupid to even think to roll her eyes, and Edna (is that her name? The least attractive sister?) lacks the irony to eye-roll, but I just noticed that others were doing this, and using words like, "sure" and "all right" which seemed too modern somehow.

Aside from this, the episode had many uninteresting side stories--I couldn't tell you which one was the least interesting--perhaps the new maid in cahoots with the conniving butler--and there were a few times where what happened was a little too convenient (Lady Crawley happening to overhear Nanny Bumpo speak a racial slur to the young "half-breed" baby; that one lad running into Anna and that pretty visitor slumming it at the dance hall, same pretty visitor being able to change into a maid's uniform in fourteen seconds and change back again). But still, but still. It's better than any episode of NCIS or CNIS or Law and Order or Two and a Half Men, for Christ's sake. For the sets and costumes alone and Maggie Smith's sometimes weak, sometimes pithy one liners, I'll continue to watch.