I was waiting in the crowded T-shirt shop to place my order when a rotund, bearded customer ahead of me stunned the sales clerk with this request: "I'd like a plain white T-shirt inscribed with the letters S-H-I-R-T. Make them big and bold. And add an exclamation mark."

A hush fell over the throng. The sales clerk mumbled "Anything you say," while exchanging worried glances with a fellow worker. From behind me a derisive voice offered an explanation: "I think he wants it for identification purposes."

There was a nervous tittering; the bearded man turned and cast a cool, appraising eye up and down the line of suddenly sober faces. "Excuse me, sir," I ventured, overcome with curiosity. "Would you be offended if I asked what it is you're trying to say?"

"Not at all," he said, surprising me with his warmth. "It's just my way of bucking the trend. Everywhere you turn these days your eyes are assailed by some message. For some reason, people feel they have to flaunt their sentiments, their prejudices, their affiliations or their religious convictions. What used to be a simple piece of clothing has become a vulgar, undignified medium."

I glanced down the line to see how many people were offended. There were more hanging jaws than angry frowns. "So why don't you just wear a blank T-shirt?" snapped one young woman.

"A blank T-shirt is fine for a non-conformist," he answered. "But I want to go beyond that to convey my own message: the anti-message. Now, don't get me wrong; I think people with blank T-shirts and bare bumpers are refreshingly inscrutable. But if you don't have something on your shirt, people suspect you don't have any convictions or sentiments."

"Weird," someone whispered with conviction.

"Okay, there's no denying that a blank shirt can be a social handicap," I said. "But what's undignified about wearing a shirt to commemorate something? I'm a runner and I've got a shirt for almost every race I've ever entered."

The bearded man looked down at the Muscular Dystrophy Marathon shirt I was wearing, which read: I RAN FOR THOSE WHO COULDN'T. Smiling sadly, he shook his head, winced and chose his words with obvious care. "Well . . . for one thing, it's incredibly pretentious. Do you expect anyone to believe you endured the agonies of a marathon purely for charity? Even if you had, the shirt would be so brazenly self-congratulatory as to make a mockery of your good deed. Look at it this way: If every race you enter is memorialized on a shirt, the truly memorable race gets lost somewhere in your pile of shirts."

From behind the counter the sales clerk cleared his throat. The shirt was ready. Oblivious to the jaundiced stares and stifled snickers, the bearded man pulled the shirt on and inspected himself proudly in the mirror. He paid the cashier and was about to leave when his face clouded with regret.

"Look pal," he said to me, "I didn't mean to take anything away from you. Whatever your reasons, running a marathon is an extraordinary achievement. But so was the first trans-Atlantic flight. And wouldn't Lindbergh have looked silly in a T-shirt commemorating it? All I'm saying is that a T-shirt trivializes and cheapens the sentiments it flaunts. Imagine the founding fathers in DON'T TREAD ON ME T-shirts. Imagine Columbus triumphantly returning to Spain with an I FOUND IT sticker on his ship. Imagine . . ."

"Next," the sales clerk barked, turning to me."What'll it be?"

I froze. Not only had I forgotten the wording for my shirt, but I was also no longer sure I wanted it. I lowered my voice to a near whisper: "I'll have the same." The clerk was incredulous. "Is this some kind of a joke?"

"Not if you ask me," volunteered the woman behind me. "It's a real novelty. I'll take one, too."