The competence of the driver. He not only had to back down my curved driveway, he had to stop on the hill at a point he could reach the tank. Having done that, he filled the tank and filled out the paperwork. Then hung said paperwork on my front door knob and drove away, smooth as silk.
Eric was great to work with. He was professional, knowledgeable, and took the time to explain exactly what he was doing so we were fully aligned on our needs.