"A Christmas Story" hasn't just seeped into the culture, it has swamped it. A tale with considerable anger is now so clearly thought of as lovable, one retail chain has issued gift cards with the tongue-on-the-flagpole scene. Still, while "A Christmas Story" is also fall-down funny, the undercurrent of disappointment is central to its greatness. It is not a case, as writer Stephanie Harrison once said of family films set in years gone by, of "nostalgia for an un-lived past." It goes more to what "Christmas Story" director Bob Clark has called "warm-hearted cynicism." Clark said that about Jean Shepherd, the radio raconteur and writer whose short stories provided the basis for "A Christmas Story." (Shepherd is also the film's narrator.) Raised in Indiana, which gave him a strong foundation for tales of Midwestern life, Shepherd became a legend as a late-night monologist for New York radio station WOR from 1955 to 1977. His stories captivated insomniac listeners. He was, not surprisingly, beloved on college campuses. More than one writer has pointed out the resemblance of "The Wonder Years" to Shepherd's narration for "A Christmas Story" and other adaptations of his work. The rouse-the-viewers moment in "Network" may also have roots in Shepherd's rallying his listeners. In one famous case, they flooded stores with demands for a book that did not exist - until a publisher finally did is-sue that ale. "I, Libertine," by the way. As loyal as fans were to his art and his endearing voice, Shepherd, who died in 1999, was not himself lovable. I encountered him once or twice when he was promoting TV projects, and he had a knack for ticking off people. In the biography "Excelsior, You Fat-head! The Art and Enigma of Jean Shepherd," a producer who worked of-ten with Shepherd says, "The only time he was happy was when people would come up to him and say how great he was." But that anger, however misplaced, fueled his work, including "A Christmas Story." Although children are central to it, "it's not really a children's film," Clark says in a DVD commentary. And biographer Eugene B. Bergmann said, "In a Shep opus, the past is seldom what one dreams it should have been." Think of all the despair that grinds through the movie. The horrible department store Santa Claus. The Old Man, played with such weariness by Darren McGavin. The furnace. The fire hazard of an overloaded electrical outlet. The lapse in taste that is the leg lamp, the twinge of regret you feel for the Old Man when it is broken - until he begins to argue about it with his wife. Ralphie's fantasy of academic success, dashed by a real grade. Flick's gauzed-up tongue after the flagpole incident. The pent-up rage in Ralphie when he finally turns on Scut Farkus; as intimidating as Scut has been, Ralphie unleashed is pretty frightening, too. Getting your dream present at last , after all those warnings - only to near-ly shoot your eye out. And finally, as Ed Grant noted in Time magazine, the ache in Shepherd's narrated acknowledgment when he refers to the rifle as "the greatest Christmas gift I ever received - or would ever receive." On the DVD, Peter Billingsley -who played Ralphie - says that people often come up to him saying, 'That was me, that was my life, that was my family." Why would they want to think that way? Because Christmas is a gift best delivered in the real world. TNT presents its annual "24 Hours of 'A Christmas Story' " beginning at 8 p.m. December 24 and running continuously through the next day, concluding with a final showing at 6 p.m. Christmas Day.