Many drivers will pull through the fuel island to run inside the truck stop and get coffee, use the restroom, etc.
While this doesn't usually create a problem, some drivers will literally park there for a long enough time that someone pulls in behind them, fuels and then ends up being blocked in because the other driver is in the truckstop taking a shower or sitting down for a meal! This author does actually endorse and recommend that women drivers pull through the fuel line at night to go in and take care of business but ONLY if it's going to be short and sweet. To keep another driver waiting because you're too lazy to actually park in a spot is terrible etiquette. Sometimes there won't be any available spots and you'll be all but forced to do this - but please, make it quick.