If you're reading these words on or about the first Sunday of 2000, chances are the infrastructure didn't fold. Thanks to a dedicated band of cyber-cassandras (most of whom were acting responsibly) and a pumped-up media (most of whom were trying to), we began taking Y2K seriously a few years ago, just in time to prevent the worst possible scenarios.

But what finally got the public's attention was not the binary-number explanations quoted by the experts, or the suggestion that Malaysia, say, might have failed to upgrade systems. It was the exponential scare factor, picked up on by popular culture and then reproduced, ad infinitum, through print and TV and computer screens across the land.

Apocalyptic gossip abounded. By the time Wall Street and the Pentagon announced they were Y2K-ready, a few folks had already moved their families and canned goods to Wyoming.

Having had a laptop crash on me in the late '80s, then flicker back on with a wiped-out hard drive and a blinking notice -- "January 1, 1900" -- I didn't need much convincing about impending perils. Others were more cavalier, certain that God or AT&T would light the trail. But wherever you were along the fear spectrum, there seemed to be a certain dark delight in all this anticipation of global mayhem. People began planning what to hoard (beef jerky, Starbucks' French roast) and where to wake up on January 1 (if the world broke apart, did you really want to be in Waltham?).

When Ken Olin showed up in late November, averting a nuclear disaster in Y 2 K: The Movie, NBC's own disclaimer seemed, well, sort of cheesy: "This program does not suggest or imply that any of these events could actually occur." Does that include having your mom save you from a really bad New Year's Eve date?

Not unlike the impulse toward gallows humor that can shield a doctor or journalist working a disaster, a lot of people turned the potential nightmare of Y 2 K into a lark -- sensing, probably instinctively, that foxhole camaraderie is a great armor. But what is it about human nature that makes us partly enjoy being frightened to death? Half the entertainment industry, from horror movies to catastrophe lit, exploits this premise, titrating trat ing our bad dreams into palatable doses in order to make them bearable. An ounce of terror, via Stephen King or Scream, may be homeopathic. And let's face it, Jon Krakauer's Into Thin Air didn't belay onto the bestseller list for months because those guys were up on Everest singing "Edelweiss."

If these defense mechanisms are irrational, so is fear itself; otherwise, we wouldn't need such elaborate counterphobic behavior to combat it. When the fight or flight instinct emerges from deep within the brain, it doesn't appear bearing analyses about why something in particular seems threatening. When horses spook or children scream, they don't stop for a moment to consider the options available to them. That ability to reflect is one of the gifts and burdens of mature human consciousness. Since a great deal of aggression is fear-based, our effort to out-think fear may be biologically protective -- it's one way the species avoids overt physical conflict. Instead, we theorize, dissect, and sublimate. Confronted with a horrid news headline or the threat of rioting in the streets, we turn it into urban legend, or tell a knock-knock joke.

The species has always had ways of psychologically diverting terrifying events: Cowering before an eclipse of the sun, ancient cultures assumed they had angered the gods, preferring their own complicity to the random unknowns of science. In the modern world -- postindustrial, postnuclear, and staggering under the weight of its own irony -- we've transformed those coping tools into a more secular form of grim equanimity. Where God used to bear the responsibility for natural cataclysms, now we've invented a few of our own; it's hard to blame a vengeful deity for a computer foul-up or a broken rope atop Mount Everest. And yet we're still transfixed by the drawing-room experience of these tales of strength-through-adversity, where somebody else gets (or has) to be the hero. Armchair expeditionists, we placate and deflect our fear by feeding it.

I was reminded of this when the EgyptAir flight went down last fall, and my mother -- a wise senior citizen who, in the landlocked Texas Panhandle, has always been suspicious of large bodies of water -- called me to express her alarm. The flight had disappeared, she said, in the ocean near Nantucket, not so far from the site of the Kennedy and Bessette tragedy months before. What did I think this meant?

Nothing, I said, eminently sensible. Thousands of flights a day take off from the Eastern Seaboard and pass over those waters; it was a simple matter of statistical odds. No fool about either weather or the laws of logic, my mother listened politely while I talked on about flight controllers, fog, margins of safety.

"Yes, dear, I know," she said. "But do you think it's something in the atmosphere up there?"

My mother was sticking to her guns; she didn't want to be talked out of her fear. She had already lost me to the Bermuda Triangle of the East Coast; who knew what other forces were at work? Later, I remembered that she had just finished reading Sebastian Junger's The Perfect Storm, which had scared her out of her wits and had confirmed the dangers of the northeastern seas, where fishermen (or daughters) could disappear with little warning. Like those people faced with a total eclipse, my mother reached out for mystery instead of reason. Better that than the cold reality of chance, where, in the formulas of computer chaos or climatology, humanity doesn't really factor in at all.