It's a gas

The young woman sat in her stalled car, waiting for help. Finally two men walked up to her. “I’m out of gas,” she purred. ‘Could you push me to the gas station?”
The men readily put their muscles to the car and rolled it several blocks. After a while, one looked up, exhausted, to see that they had just passed a filling station.
“How come you didn’t turn in?” he yelled.
“I never go there,” the girl shouted back. “They don’t have full service.’