I don't wanna overanalyze the meme, but it is irritating when you can't have a conversation with someone without their whole identity being based on whatever they've recently watched. Then if you haven't seen it, them uncreatively explaining the plot to you.
Growing up in the years before and during Cable television, I am positive television was the most talked about topic over any and all aside from basic hello.
And if you didn't have cable, well you'd get filled in on whatever, but were oddly OK with it.
It’s a shared experience, like the weather. Usually in person with somebody who experiences the same weather, but comparing/contrasting weather with friends across the country (US, so that can be pretty far) works sometimes too.