As we drove through Kentucky on our recent journey, I saw something that prompted a thought. It was raining, and hilly, and there were a great many tractor trailers on our two lanes of the highway. Camping out in the left (good drivers translate that word into "passing") lane was a fool of a man in a spanking new pick-up truck. Occasionally he would realize there was a semi about to copulate with his Chevy, and he'd speed up and get over into the right lane. But, just as sure as there's moonshine in those old Kentucky hills, this nitwit would ease back over into the left lane, and jam up traffic again.

And, because the terrain was hilly, and because it was raining, and because the road was littered with tractor trailers, more than once a whole series of sudden braking actions would occur, as trucks on a downhill, blocked by this menace, would hit their brakes, setting off a chain reaction a mile back. Twice there were nearly accidents, and for all I know he eventually did contribute to someone's death or injury; we left him behind at the first opportunity.

The thought that stuck with me is that, had this fool contributed to an accident, odds are he never would have realized it, because it would have taken place somewhere behind him. Bad drivers are often like that -- totally oblivious to the fact that they are dangerous to others. This got me thinking about that class of person in general, the Oblivious Menace. He is the person who sneezes in a public place without covering his mouth, or the restaurant employee who goes to the bathroom without washing his hands afterward. He is the manager who destroys morale but fancies himself a hard-nosed leader. He is the employee who is too stupid to follow procedures, making mistakes that his company will pay for in lawsuits and government fines long after he has moved on or been fired. He goes through life doing things that well-trained adults know are uncouth, leaving a host of sick, injured, and unemployed in his wake, and never has a clue that on net his contribution to society is negative.

One doesn't have to cause harm to qualify as an Oblivious Menace, of course, because at root we are talking about behavior that escalates the risks of harm to those in one's vicinity. To be sure, there are people who do so consciously -- aggressive drivers, for example -- but for some reason people who increase the risk to my safety without being aware of it make me more wary, perhaps because their behavior is less predictable. One expects people to cut into one's lane from time to time; one also expects people to cover their mouths when they sneeze. Surprise with regard to the latter is unnerving. Self-centered jerks are predictable, but unmindful walking hazards are like landmines -- we know they are out there, but we are never quite sure where, and we are always unpleasantly surprised when they cross our path.

Just yesterday, for example, we were on a North Carolina beach when an old woman appeared, walking a slathering, growling bulldog. It was all she could do to keep him going in the direction she desired, rather than in the direction he preferred. He was clearly unfriendly and dangerous, and by stumbling about in the sand with him, she was exposing all of us to considerable risk of injury. Had one queried her about the furry ball of muscle and drool at the end of her leash, however, she would have no doubt insisted that he is in reality the sweetest creature on God's earth. She is, in short, an Oblivious Menace.

I recall during one of my daughter's hospital stays, when her white cell counts were dangerously low, I had to repeatedly remind one of the nurses to wash her hands before tending to Caroline. One of the first things one learns when working on a pediatric oncology ward, I think, is to wash one's bloody hands. They even install a handy antibacterial foam dispenser by the doorway to each patient's room, to make the essential action easier. Still, I had to tell Nurse Menace to wash her hands. I also had to tell one of her colleagues that one musn't flush Neupogen with saline, but must use sterile water, or else the effectiveness of the medicine is diminished. I'm not an oncologist, but I learned this because I had a considerable stake in getting it right. One would think the same were true of the nurses.

Mistakes like these, when combined with other sloppy behavior commonplace in hospitals (and elsewhere), kill people. What's maddening is that these Typhoid Mary's usually have no clue when their negligence contributes to illness or death. Like the witless Chevy driver on that stretch of Kentucky highway, they survey the wreckage behind them and go on about their business with a cluck of the tongue and a shake of the head: Oh well, accidents happen. Tough break.

Sure, accidents happen, and for the non-Reformed life is full of happenstance. But much of what happens has a human component, and frequently, I suspect, a component of human error. This is why insurance companies find it prudent to raise rates on customers who submit a claim for an accident. They have found that statistically, such people are significantly more likely to be involved in future damage. This is likely to elicit howls from some readers. How can it by my fault, after all, when someone runs a red light and broadsides me? Or when, while working on my garage roof, a weak beam gives way and I fall through?

Indeed. To the Oblivious Menace, these are real posers. To the rest of us, there are a thousand ways the careful person avoids such accidents. That is not to say, mind you, that we have some culpability for every accident that befalls us. But there is a wide stretch of culpability remaining between clear malfeasance and accidents that do not leave one legally liable.

The most disturbing thought is that I -- or more likely, one of you; I self-monitor to a pathological degree -- may be an Oblivious Menace in some walk of life. It's that Oblivious part that may be keeping us from recognizing it. I imagine it all turns on self-awareness; most of us pay a modicum of attention to the impact our behavior has on our surroundings, others can't see the world in any but solipsistic terms. With that in mind, I propose a test to determine whether someone is an Oblivious Menace. Before you hire someone, or let him drive your children about town, sit him down and talk to him for five minutes. If I'm right, and the root cause of Menacing Obliviousness is extreme self-centeredness, then an Oblivious Menace will likely be one of those people who turns the conversation to himself (and this is one instance where I think it is imperative to supplement with "or herself") regardless of the topic or context. You say you are getting tested for cancer, the Oblivious Menace will start talking about the time he had to be tested for Lyme disease (never mind that it turned out negative, what's important is that he tell you how he feels). Mention that you just got promoted, and the Oblivious Menace will start prattling on about some mundane aspect of his own job.

My prediction, in short, is that the Oblivious Menace is not just a physical menace, but a conversational one as well. Rather than seeing the world, he sees himself in it. He lives, as we used to say of a friend who I'll call "Terry," in a Terry-centric universe. And in the end, I think this is by far the worst type of menace, because while life will always have physical hazards, people-imposed tedium shouldn't be one of them. As Clint Eastwood's character said in "Heartbreak Ridge," "You can beat me, you can rob me, and you can kill me, just -- don't -- bore me."