With the threat of nuclear attack being stressed repeatedly the 60s 70s and 80s must have been terrifying at times. All it would have taken was for someobdy in a position of power to cause a panic during the Cuban missile crisis and goodness knows what might have happened. Also Castro was prepared to launch the missiles had the Americans attacked. Look at the Oscar winning documentary the War Game (1965) and you'll see how and the protect and survive ads from the 70s and you'll get a snse of how seriously people in the UK were taking the nuclear issue.
Yes, it's as chilling as the real thing was. Suddenly everyone had to have a fallout shelter in their yard. We had duck and cover drills in school, and every time they interrupted a TV program for a test of the Emergency Broadcast System, we thought that was IT, that the missiles were on their way to both continents and we had minutes to live. Those of us who were kids then didn't expect to grow up.
We had a half-suppressed belief we wouldn't survive until adulthood. As a member of that generation, I am sure this apocalyptic dread fueled both the antiwar movement and the Sexual revolution. The same sense of crisis that fosters (in my experience) promiscuity around ER's & OR's did so for our whole generation.
It's hard to say which is more frightening regarding surviving or not when it comes to these kind of things. The Blitz, Allied bombing in Germany and japan not to mention any bombing campaign from 1972 onwards involving a b52 may have seemed near apocalyptic for the people on the ground. Also regarding the Cuban Missile Crisis there were apparently more rockets than our intel had picked up so thank god we dodged a bullet there.