Watching this video could save your life. At the very least your vehicle, and everything therein. Fires at the gas pump are rare but in any case, mother nature, along with assistance from the driver is the culprit.
The Petroleum Equipment Institute, warns drivers about this problem and says "avoiding re-entry in to the vehicle is the best way to prevent static electricity from igniting your gas tank."
As a backup plan if you do re-enter during fueling... When you exit your vehicle ground yourself out by touching the metal part of your door.
You may receive a little shock, but better than a fire.