Who tips at food carts?

Maybe I am out of touch. 

I never tipped the hot dog guy. 

A fed-up cook who worked at the popular food cart Milk Truck was canned for using Twitter to call out Wall Street executives who racked up a huge tab and didn’t leave a tip.

“I’ve had plenty of food-service jobs and I’ve kept my mouth shut — but this time I figured, I’m sick of this,” cook Brendan O’Connor, 24, told The Post yesterday.

O’Connor was flipping fancy grilled cheeses near the South Street Seaport in the Financial District on July 22 when a group of workers from the financial firm Glass, Lewis & Co. ordered about a dozen sandwiches and five milk shakes — totaling $170.

The group failed to add gratuity, and when O’Connor asked if they meant to stiff him, they blew him off, he claims.

That’s when O’Connor took to Twitter to vent.

“Shout out to the good people of Glass, Lewis & Co. for placing a $170 order and not leaving a tip. @glasslewis,” he tweeted directly at the company.

Honchos at the firm contacted O’Connor’s boss, Keith Klein, who fired him two days later, O’Connor claims.

Klein, according to O’Connor, is a social-media control freak — scolding employees if customers posted sandwich photos on Instagram or Twitter that looked anything less than perfect, even if the shots were accompanied by positive comments.

I tip for service. I don't tip at MickeyD's. The employee there does the same job as Mr.O'Connor. I pay for the waitstaff who refills my drink, places the food in front of me, cleans off the dishes......