In Canada, unlike in the United States, we need to apply continuous pressure on the trigger of the gas nozzle to maintain the flow of gas. The amount of pressure required to squeeze the trigger is not only hard to do, but tends to accentuate ulnar drift - the swelling in the MCP joints (big knuckles of the hand) that causes the fingers to drift towards the baby finger.
I've found that when I turn my back to the car and face the pump, it is easier on my hand. Then when I squeeze the lever, it appears to counteract the tendency to push my fingers into an ulnar drift.
If you do try this, please let me know if it makes fueling up a little easier for you.