[quote=@Monkeypants]
Asshole gas station attendants. Sure, you hate your job but shit man, cheer up. You have the simplest job ever, put stuff on a shelf and ask if it'll be unleaded. No one pays with cash anymore so you don't even have to handle money. Hell, most have card readers at the pump so you don't even get half the internal business as before.. And yet attendants can be sheer buttholes to their customers.

I mean damn, if you hate it... Just quit?

/endrant.
[/quote]

If you quit you don't get paid. They ain't there for fun.

That all being said, I've done jobs like that and absolutely hated it the entire time. What I can say is that there are other people out there making them hate it. I would venture to say most of the cheerful ones you've talked to are just really good at their customer service game and hate you even more than the surly ones (makes me think back to working in a booth where sound basically didn't communicate between inside and out unless you came close to the speaking hole, so everyone else in the booth was making merciless comments about a customer while they were talking to the employee stuck with them).

But the original point, yeh, it isn't the average person paying with a card and getting out that makes them hate their job. It's the people who come in and pay in loose pocket change, or the people who find it appropriate to stand there and BS for forty five minutes. It's the woman who shat the entire bathroom at once, the kids who show up with no intent to buy anything and require you to watch them so they don't pocket anything, and the homeless guy with a bowie knife on his hip who falls asleep in a stall in the men's bathroom. My favorite to this day that I ever got was a woman who's method of shopping was to bring a bunch of shit to the counter, toss a random bunch of money at me, and ask if she had enough to buy all the shit. If I said no, she wouldn't take a few things off, oh no. She would leave all that shit behind and ask me to put it back, then she would go get a whole other batch of shit and ask me if she could pay for the new stuff. You also get people too drunk to be trusted, methheads peddling obviously counterfeit cash, and situations where a lazy parent sent their kids to do their shopping and thinks it is appropriate to phone in a credit car number. And all of that, that is just the shit I had to deal with at one time or another. And I was never in a position quite as precarious as a gas station attendant. 

So when you see a surly gas-station man, have pity. There but for fortune go you or I.