Though it may not be the principal thing we critics do - which seems to be infuriating readers with the insensitivity of our observations - most of us spend a good deal of our time handing out knocks. It's unseemly and unfair, many people say, and they're probably right. In any case, in accord with the seasonal predisposition toward generosity and beneficient feelings toward one's fellow creatures, I've decided to do something about it this year.

To make up for all those verbal brickbats, and to show that my heart is in the right place, if not always my head, I've determined to play Santa this week (something I've wanted to do since I was a wee, small delinquent) for some of the targets of past critical abuse.

Therefore, if the persons or institutions named below will look under their respective trees this morning, they will find, swathed in plain brown wrappers with no return address, the following items:

For Livingston Biddle, the new chairman of the National Endowment for the Arts: a keenly sharpened, ivory-handled machete from the jungles of Borneo, for fending off the special pleaders, influence peddlers and congressional pork-barrelers who'll besiege him daily, now that the arts funding pie has grown big enough for every taxpayer to want a slice; also, a tin cup, for his annual trek to the Hill for more and ever more appropriations; and also, one deaf ear, to be turned this way-or that as the occasion warrants, which it will unceasingly.

For Rudolf Nureyev, the Russian dancer seen in movie theaters this year as the pilloried hero of Ken Russsell's "Valentino" a film scenario more commensurate with his unquestionable screen magnetism and his artistic gifts; also, a director with a smidgeon of taste.

For Wolf Trap Farm Park for the Performing Arts, which will play host next summer to the first Red Chinese ballet troupe to visit this country: a lake-sized tureen of hot and sour soup.

For Cynthia Gregory, the ballerina who defected a second time from American Ballet Theater this year, complaining of the lack of male dancers to her liking: the ideal ballet partner, with one arm fixed permanently upward in a lift position, and the other blowing non-stop kisses in the direction of his dance mate; also, and easy-to-pack matched luggage set, for quick getaways; also, a reusable press release announcing her retirement and/or return to the company.

For Zelda Fichandler, who now has three threatrical spaces in which to operate - the Arena itself, the Kreeger and the Vat Room - a fourth stage, from which to present all those worthy dramatic properties that won't wash in the other three, either because they won't fit or because they're unsuitable; things like a revival of "Life With Father" and the lesser-known masterpieces of Plautus, Kleist and John Lindsay.

For Gelsey Kirkland and dancer whose indisposition last year prevented her assuming the ingenue role in the ballet film, "The Turning Point": the female lead in a new feature in the planning stages at a major Hollywood studio, a sequel to the above to be called "The Point of No Return." The plot concerns two men in love with the same exquisite young ballerina (Kirkland:) one a cynical idler, filthy with family money, the other a starving, unknown choreographer. Rudolf Nureyev and Mikhail Baryshnikov have agreed to be the male principals, but there seems to be rather intense dispute at this point over who should play which role; meanwhile, Fernando Bujones have volunteered to tackle both roles simultaneously, and the producers, naturally eager to cut costs, are said to be thinking seriously about the possibility.

For Roger Stevens, chairman of the Kennedy Center: a compass, to thread his way through the plywood labyrinth that is the Kennedy Center lobby these days, while the long-delayed roof repairs still await completion and "temporary" scaffolding turns the Grand Salon into a rabbit warren.

For WETA producer Ruth Leon, who will be producing the first performance telecasts from Carnegie Hall for public television, having snatched this program plum from right under New York's own WNET: a well-sized banner reading, "Eat Your Heart Out, Channel 13!"

For choreographer Paul Taylor, whose new commissioned work for ABT, which was to have been his first for a classical ballet troupe, could not be finished in time for its planned Kennedy Center premiere: six months of paid-for rehearsal time.

For George Stevens, whose American Film Institute celebrated its first 10 years recently with a network TV show that mixed film clips with wall-to-wall Hollywood stars: the 200-inch telescope on Mount Palomar, the better to focus in on those stellar objects of AFI attention; and also, a third hand, to make it easier to pat himself on the back, without interfering with his other executive and administrative duties.

For the chef of La Grande Scene, the Promenade and the Kennedy Center Cafeteria, the Center eateries that will be closed for months while the roof is being repaired: copies of "How To Boil an Egg" and other classic tomes on culinary fundamentals.

For Natalia Makarova, who's taking time off from her illustrious career as a ballerina to have a baby: a bassinet with a built-in barre and mirror, to start the new addition off early on the right foot.

For Glen Tetley, whose ballet "The Sphinx" was given its world premiere by ABT this season at Kennedy Center: a new answer to the riddle of the Sphinx - What animal walks on four feet in the morning, two feet at midday, and three feet in the evening? The ancient answer - man, as a crawling toddler, an adult and a cane-wielding senior citizen - is wrong. The true answer is, a dancer in a Tetley ballet, who grovels on the floor through most of the rehearsal, stands erect only during noon recess and needs a crutch after the performance.

For Akira Endo, the controversial ducted most of the company performances in Washington this season: a metronome.

I'm just kidding about all this, of course. Just the same, I'll end by repeating a line Johannes Brahms once used on leaving a party he'd attended: If there's anyone I've forgotten to insult, I apologize.