I'm not a hugely confident driver at the best of times, but petrol stations bring out the worst in me. I think the problem is you can't talk to the other people like any other queueing situation, to ask if they're waiting for that pump, or why they're not moving forwards. The worst is the dilemma when the front pump is full but the back one is free. Do you use it, then watch the front pump empty, but inaccessible to cars behind you? Or wait, and use the front pump, but spend all that time with the back pump waiting unused. STRESS.