If the pumps are busy I fill up and repark to go inside, then I'm not wasting anyone's time.
I do that even if they aren't busy. Fill up, park the car, then go inside. It makes life easier for everyone.
The way the guy was, he may have came out shooting thinking OP was pumping and running.
I am sure the worker would tell LEO to never return too, but expect them to help when his store is being held up.

As insinuated many times in this thread, people are nuts.
It was probably the fact that I looked at two trash cans to see if their were any paper towels in them, so I could clean the dirt and grass out of my oil measuring cup to measure the oil for my 2 cycle equipment. A process that takes 10 seconds. It's probably what pushed him over the edge because I had to search through my truck to find my own paper towels, and maybe that's when he thought I was just dicking around. That kind of thing irritates me so after that I assumed it was probably one of those independent gas stations with one owner who's a cheap skate. Boy was I right. lol
Around here you must pay before you pump, so they're probably not going to come out shooting thinking I'm running. I hope! I pull up, go inside pay cash, then pump. If I have to take a leak, or buy something I move the car to a parking space as soon as I'm done pumping. I see people cleaning their trunk out, making potty runs, emptying ash trays, washing all their windows, shaking out floor mats, etc. even when there's a line. All those things I take care of at home! Or if I'm on a trip in a parking space. But as you said people are nuts, my gas pumping routine is in hope to give a nut one less thing to go nuts over.
Somewhat OT- lately, maybe its the heat wave, people are doing some really stupid things while driving. Much more than what I'm accustomed to seeing.