I refuse to use the Shell / Coles Servos as their stupid 4 cent voucher generally only brings the price back to the same as all other servos, so it's a false economy of 4 cents off.
As far as filling and paying, if I have people waiting I'll jump back into the car after I've finished filling and move the car over to one of the parking bays. 9 times out of 10 you'll get a polite "thank you" from the guy behind and I'll wave back, but if it's a female they'll never say thanks. Don't quite know why they are so much more ignorant than males.
"Common courtesy" goes a long way, sadly it's just not that "common" these days.
Cheers,
BB.