Attendants at full-service gas stations often check oil and wash windshields in addition to pumping gas. They may also check the level of other liquids, including water and windshield washer fluid.
Before the 1970s, most gas stations were full service. It was expensive to keep attendants on staff to pump gas, and this cost was passed along to the consumers at the tank. As gas prices rose and consumers were more interested in saving a few pennies instead of having someone else fill their cars, many stations changed to a self-service model. Most of today's gas stations continue to follow the self-serve model, although there are a few full-serve stations found in most regions.
In Oregon and New Jersey, it's illegal for consumers to pump their own gas. New Jersey's law has been on the books since 1949, and it stemmed from a number of perceived dangers, such the inhalation of gas fumes and the risk of crime or fall-related injuries. Lawmakers also felt that having pump attendants on staff would create jobs. While the cost of the attendants does raise the price of gas by a few cents per gallon, New Jersey has one of the lowest gas taxes in the country, so gas ultimately costs a bit less in the state compared to neighboring states.