As children, we are taught that -- when it comes to people -- you can't judge a book by its cover: Make certain, our elders say, you at least get to know somebody before deciding you despise them.

As adults, however, we forsake such rules, and often (quite legitimately) rush to judgment about certain types of people whom we know should be avoided.

There is, for example, the Ph.D. candidate who spends two weeks in London and returns with a heavy English accent, which lingers a month later. Also included in this group are women who use cigarette holders in restaurants; street mimes; college athletes who refer to themselves as "the kid"; most Corvette owners, and a man with a beard, but no moustache.

Even these people, while certainly not types you'd want to spend an evening with, are usually at least tolerable for short periods of time. There are, however, individuals in this city with instantly recognizable traits that make any sort of socialization completely out of the question.

Here are the worst offenders:

People who whistle on public transportation.

They should be fined for disturbing the peace and permanently exiled to New Jersey. If someone is happy, they should sit quietly and not disturb others trying to read about the prospects of a Republican administration. If the whistling is the result of nervousness, the afflicted person should undergo behavior-modification therapy to either eliminate the habit, or alter it to a less annoying mannerism, such as drooling.

But if these warblers feel compelled to persist, they should eliminate tunes such as "Bridge Over the River Kwai" from their repertoire and concentrate on numbers a little less catchy, ones which will not stick in other people's minds for the rest of the day.

Men who drape their sport coat over their shoulders like a cape.

These refugees from magazine ads, most often found in Georgetown, invariably have blow-dryed hair, a degree in business administration from a two-year college, and a Maryland license plate with a catchy nickname on it.

Joggers who run in place while waiting for a traffic light to change.

Chances are these people, a significant percentage of whom are rumored to be supergrade government employes on flextime lunch breaks, have other annoying affectations as well, such as smiling before breakfast.

Bouncing up and down as if trying to tolerate a hot, sandy beach has nothing to do with exercise, and there is no reason why pedestrians windowshopping on K Street should have to be witness to such behavior. Anyone who likes running in place should confine workouts to the privacy of their living room or office.

Anyone who uses an umbrella in the snow.

This person considers painting of bright orange tigers on black felt to be art worth investing in. Unlike rain, which usually serves no purpose other than to trap you at undesirable places (such as family reunions or congressional hearings), snow is pretty and meant to be walked in, played with, enjoyed. People who shield themselves from snow in such a manner tend also to wear long-sleeved shirts and pants on the beach.

People known only by initials, rather than a first name.

This group of people is truly unique, in that they are able to elicit feelings of abhorrence from those with whom they have never come in contact. Consider, for example, the following problem: You receive a letter from J. A. Schoenholtz, a State Department official whose gender is unknown to you. When answering the letter, what do you say in the blank: "Dear Schoenholtz"?

Or do you just address it: "Dear J. A. Schoenholtz"; and admit to this person that you have absolutely no idea who he/she is -- thereby possibly jeopardizing a major business deal or an appointment to the Foreign Service.

The only times initials are an acceptable substitute for a name are:

(a) when a living person is instantly recognizable, leaving no doubt as to their identity, such as J. D. Salinger or J. R. Ewing; (b) when a person is deceased, and you won't have to answer their letters or phone calls; and (c) when a person has a sneaker named after them, like P.F. Flyers or U.S. Keds, raising them to a special status.

The elevator expediter.

You approach an elevator bank and press a button, which lights up. Moments later, a person walks up beside you and stands staring at the closed doors, shifting from one leg to another, and muttering under his breath, about how long it is taking.

Then, apparently not convinced your actions will be at all effective, he presses the same lit button, as if to inform you that he will now take over and speed you both on your way.

Invariably, the elevator arrives posthaste, and this egomaniac gives you a quick, pompous grin as you follow him into the car.

In such situations, it is acceptable to whistle "Bridge Over the River Kwai" until this varmint disembarks, with the tune seared, it is hoped, indelibly in his brain.