Am I the only post-40-year-old who remembers the joy of ticking off old people by wearing a smart-aleck T-shirt?

I wondered about this amid the coast-to-coast grumbling over Urban Outfitters, the Philadelphia-based clothing retailer that recently pulled from its stores a T-shirt that said, “Voting is for Old People.”

Imagine. Young people mocking the habits of their elders. Why, next thing you know the young will be making fun of old folks’ clothing styles, driving habits and comb-overs. Horrors.

As a kid, I had several T-shirts that caused oldsters to bristle. One of my favorites was emblazoned with marijuana leaves and the words “Ganga University.”

Most old people at the time had no clue what ganga was or what a pot leaf looked like, so the joke was on them.

“Where’s Gang-guh University?” they’d ask.

“Jamaica,” I’d say.

In 1976, when I was 15, America celebrated its bicentennial and the “energy crisis” was still upon us. People scrambled to downsize from four-barrel road hogs to teensy, foreign-made gas-sipping tin cans.

I had a red, white and blue T-shirt that said, “Eat Beans — America Needs the Gas.”

It’s benign today, but back then old people sneered at the implied gas-breaking humor. It was so impolite, so “common” as my grandmother would say.

We can thank — or blame — John Keddie for reviving the faded art of subversive T-shirt slogans. His Internet company, VintageVantage.com, sells rare old T-shirts and he designs new ones to look like old ones, including “Voting is for Old People.”

He’s puzzled by the fuss.

“The intent of the shirt was just to be funny. It was a joke. It was never meant to be any political instruction,” he said from his home in San Diego. “People are trying to say we are trying to make voting uncool or unfashionable. That’s just not the case. Our customers appreciate our sense of humor. Kind of witty, irreverent sense of humor. That’s who the shirt was designed for, those kind of customers.”

Still, it didn’t amuse Dan Glickman, director of the Harvard Institute of Politics, and a Harvard student, Ilan Graff.

“The shirt’s message could not be further from the truth,” they wrote to the CEO of Urban Outfitters, and suggested the company sell a shirt that “better reflects the considerable social conscience and political participation of today’s youth. You might consider ‘Voting Rocks!'”

Drips.

Actually, the shirt is accurate.

In 2002, the University of Maryland found that voting by Americans ages 18 to 24 had declined 13 percent in presidential elections between 1972 and 2000. In 2000, only 42 percent of 18- to 24-year-olds showed up at the polls, compared with 70 percent of those over age 25.

Election after election, America’s youngest voters cede their political clout to old people. And when you’re of an age when T-shirts adorned with snappy slogans and hipster bands define your personality and politics, then anyone over 25 is old.

So, yes, Voting is for Old People.

And if older folks are annoyed with youthful T-shirt slogans, I suggest a way to get even when the youth culture mocks.

Mock back.

For example, getting fleeced with ever-rising property taxes has many grayheads on fixed incomes demanding relief and reassessment.

If you’re among them, put this slogan on a T-shirt:

“Property Taxes are for Young People.”

Or, “Hey, you lousy kids, get off my lawn!”

Or, “Driving Slow Rocks!”

Or, “Social Security: I Got Mine.”

Or, “I keep my turn signal on just to annoy you, punk!”

Or, “Age is just a number and yours is way small, dude.”

J.D. Mullane is a columnist for the Bucks County Courier Times in Levittown, Pa.