Hi again, MissM. Paying customer calling.
Miming to the safety briefing? What are you going on about?
The cartoon briefing is on the video screen - the CC point at the nearest doors [the first thing I check personally, and cross-check with the OH].
You say that arming the door is not the most intellectually challenging "flight safety exercise". Do you know what happens to the door when doing it? And, do you know how to do it yourself or do you think it's all about moving your arms a bit, touching a few bits on the door and giving the impression that you are actually doing SOMETHING?
Technically no, other than it is something you are
told to do by the Captain of the Aircraft. My guess ... it's related to auto-deployment of slides against possible ground hazards? Oh, BTW, I assiduously read the Emergency Cards to ensure I know how to get out if the CC are unconscious. My life depends on that ... and the pilot.
Why are you always slagging off cabin crew for their duties? Do you actually know what we are doing? Except miming to the safety briefing and doing less intellectual challenges of course.
I'm not "always slagging off" ... I am DEEPLY disappointed in the standards of BA Cabin Service in J on L-H out of LHR. Oh, and of course the fact that BA CC are trying to disrupt my travel plans and potentially lose me holidays, and business trips, and money ... but don't let that worry you, please. Continue to be "primarily for my safety" if the flight I booked and paid for actually happens.
Do you understand where I'm coming from yet? 
Manifasted poor customer service onboard? Only at LHR WW?
Superb service JER-LGW, despite the time constraints on a very short sector.
Excellent service LGW-MLA, friendly and cheerful.
Consistently inconsistent and sub-standard LHR-IAD.
Next question to your paying customer, please.