I think one of the scariest things for me was that it was set in the north of England where I'm from. Normally disaster movies are all about London and the south-east corner of the UK if they are set in the UK at all. I'm from the North West, and it was the sheer ordinariness of the people that they managed to capture so perfectly that made themselves empathetic to me. It actually felt as though I might have known some of these people. I think it was that deep empathy that made it much easier to place oneself in their position, fucking terrible position though it was.
You know, I was thinking about what you said about fearing nuclear annihilation and I think I'm more worried about it now. At least in the good old days there were only two likely candidates to start lobbing nukes about the place, these days who knows who's going to be the first to set one off.
I just don't see people living in fear that any day might be the day that the entire world ceases to exist as we know it. For instance, I'm guessing that grade schoolers don't have a nuclear attack drill (which were laughable, now that I think back).
Personally I fall into that camp, but if I woke up one morning to find out that some large city had a nuclear device go off in it via a terrorist attack, or (purely an example) Israel dropped a bomb somewhere in Iran, I wouldn't be surprised at all.
But yes, I don't think anybody would be surprised if there was a limited exchange between Iran and Israel one day. Or maybe a container ship containing a nuke goes off in a harbour somewhere in a terrorist attack, we'd be horrified, but not surprised.
The thing that struck me as a kid was the mental image of two groups of generals and leaders sitting over a map, one in Downing Street and the other in the Kremlin. I always wondered why they didn't just play Diplomacy[0] instead, but play for real countries instead of the imaginary ones in the boardgame. They still get to do all the scheming, backstabbing and other diplomatic shenanigans that politicians seem to love but without the loss of life and destruction.
Not sure my idea would gain traction these days though!
The reason is, of course, the metagame. The first one to drop a real H-bomb on the other or launch a real assault would win, hence both sides need to play at the least simulated level available.
Also, you have just reminded me of ST:TOS episode "A Taste of Armageddon", where two planets fought a virtual war in which computers simulated the mutual bombing and after such fire exchange a computed number of people were euthanized.
Those kids who talked about being scared by TDA obviously didn't watch Threads at the time. I still shudder thinking about some of the scenes.
I did rewatch it not too long ago and just kind of shrugged. I suppose that's a statement on both how far we've come in terms of actually fearing nuclear annihilation as well as the graphicness of horror movies.