I don't know if it's the same way now, but when I went to Oregon a couple of years back, it was illegal for the customer to pump their own gas. They had gas attendants who pumped the gas for you. I thought that was so bizarre.
Around here, you have to pre-pay before you get gas in some places, while in others if you use your credit card, you don't have to go inside to pay, you pay at the pump. One place I use to go to had a machine that you could either pay cash or use a credit card at and you didn't have to go inside. It varies, depending on the station and the locale.