The courteous exchange:

Stuck driver: "Thanks for getting me out, let me give you a little cash for your troubles."

Rescuer: "Thanks for offering, but it's no problem. Hopefully if I ever get stuck, someone will be nice enough to pull me out."

My mom ran out of gas one time on the highway. Lucky for her, it was a diesel. A semi pulled over, gave her gas. She offered to pay, he declined with the same response - hopefully if I ever have it happen, someone will help me out.
_________________________
"Nature has constituted utility to man the standard and test of virtue. Men living in different countries, under different circumstances, different habits and regimens, may have different utilities; the same act, therefore, may be useful and consequently virtuous in one country which is injurious and vicious in another differently circumstanced" - Thomas Jefferson, moral relativist