IF you place an order at the Chick-fil-A drive-through off Highway 46 in New Braunfels, Tex., it’s not unusual for the driver of the car in front of you to pay for your meal in the time it took you to holler into the intercom and pull around for pickup.

“The people ahead of you paid it forward,” the cashier will chirp as she passes your food through the window.

Confused, you look ahead at the car — it could be a mud-splashed monster truck, Mercedes or minivan — which at this point is turning onto the highway. The cashier giggles, you take your food and unless your heart is irreparably rotted from cynicism and snark, you feel touched.

You could chalk it up to Southern hospitality or small town charm. But it’s just as likely the preceding car will pick up your tab at a Dunkin’ Donuts drive-through in Detroit or a McDonald’s drive-through in Fargo, N.D. Drive-through generosity is happening across America and parts of Canada, sometimes resulting in unbroken chains of hundreds of cars paying in turn for the person behind them.