[Sundae]

Snort. Don't remember the episode but I would almost definitely have seen it.
And I can see it in my mind just from the character names and your description.

There's an advert for Netflix on at the mo.
Irritates me like a hair in my bra.
It's American (NO! Make adverts for your audience!) and the woman talks really fast. I had it on SkyPlus, so I could rewind it. And I did. And I still couldn't get everything she said. And no, it didn't work because I didn't buy.

But the premise - which was kinda fun - was that this woman looked over people's shoulders or at their purchases etc and told them the endings. Then when she got home - and there were other people there! how she manage that as such an annoying bi-atch? - she was flicking through Netflix. Seen, seen, seen, oh! not seen! Another lady in the room, who may or may not have wanted to kill her (shiv in back by the end of the night is my guess, given the blankness of her eyes) says, "Her sister is really her Mom."

Ha, ha, ha, everyone gets what they deserve. WTF?

Am still trying to work out the films and or series.
Lost is obvious. And I know I got another one but it's not coming to mind.