I believe Oregon and New Jersey are the only states that make full service mandatory - it is actually illegal to pump your own gas in those states.  I can't recall if this is for convenience to drivers to those states having a high degree of drive-off's without paying.  At any rate if I lived in those states I would not tip - as I don't believe a tip should be mandatory to fill up the tank - so getting full service at a gas station in any other state would be a luxury, thereby deserving of a tip.  I think 20% is generally a good standard when in doubt - however in this case I would tip $2.

I was just in New England and found some full service stations. I was at a Gulf Station in Maine and tipped the attendant. He was a little old fellow and appreciative.

I am shocked by some of the comments of my associates on RIA. The attendant is a little guy and is not responsible for the high price of petrol. That is the result of many things, economics, politics, and other forces. The attendant is just trying to make a living. He doesn't own Standard Oil or probably even the gas station.

I usually round off and don't use a formula. Sometimes it is higher and sometimes lower.

If somewhere on this universe you find a full service station and the little ole man comes out and says "hi", checks my oil & tire pressure, cleans my window, takes my money, makes me change, and says "have a nice day" then either he needs a tip or Im in the twilight zone!

Would I tip my cellmate in jail after he raped me?

Never even heard of this one. We must be way cheaper here in Canada.

I don't know...I haven't seen one since some time the '70's.

They're a rare breed. I've only ever had to do this while driving up from Maryland to Massachusetts and back (through New Jersey). And I haven't really driven by there for a long time.

First of all, the only time I use a gas station attendant is while traveling through the stupid state of New Jersey, where it is mandated that only employees of the station can pump gas. If the guy has a good attitude, maybe washes the window while I'm waiting for the gas to fill up, I might give him a dollar or too. It definitely isn't something I do all the time.