I gotta agree, I keep thinking the same thing as Swede...what do you tell the kids all those times they were on the brink of destruction along with the Enterprise and how many counselors would you need to keep them from growing up as traumatized wrecks?
I grew up in the height of the Cold War, and spent most of my childhood in a climate of constant fear that the world was on the brink of nuclear annihilation. You know those warning sirens that go off to warn of severe weather? They were originally air-raid sirens to warn of incoming Soviet nukes or bombers. I even remember having to do a nuclear-defense drill in school that, while not literally a duck-and-cover drill, was just about as futile (huddling in the hallways wasn't much better than hiding under your desk).
Granted, I only grew up under the abstract threat of doom, not actual enemy fire. (Although I grew up in tornado country, which can be pretty darn scary.) But I had a friend in college who'd been a child in Vietnam during the war, and she'd just seen the violence and death around her as an ordinary part of life and taken it in stride. Whatever we grow up with, that's normal to us.