Mazey Day might be one of the worst episodes that Black Mirror has ever done. I am like you in that I have seriously enjoyed the series in the past but feel as though they are losing their way. Mazey Day doesn't even make sense as a story at all. Werewolf? What? When? How? Did the car crash turn her into a werewolf? This isn't a surprise so much as it is just stupid.
I suppose the only thing that I found interesting about this was that even at the very end the Paparazzi were only interested in benefitting themselves, even in the final moments of the episode.
I agree that episode was embarrassingly bad and felt like I'd just wasted 40 minutes of my life.
Mazey Day felt like an episode of anything but Black Mirror. The whole werewolf theme was pulled out of thin air.