I must disagree about the self-check lines being quicker.
If there is an open line with a human checker, I go there.
I'll beat the pants off anyone checking themselves.
Anyway, I'd say that rudeness is on both sides of the "counter."
The worst kind of "rudeness" comes from the person on the other end of a phone line that works at a monopolized public utility, whether they work for the gas company, the electric company, the phone company, they all can be as rude as they please, because what am I gonna do, switch electric companies?
But really, I've been in all kinds of service jobs. Thank god I am no longer and hopefully never again! But when some pizza delivery guy or someone behind the counter and Burger King is being short or even "rude" I shrug it off. If I were in their shoes, I'd be rude as hell.
But "rudeness" is really in the eye of the beholder.
In most circumstances I am like crashfrog.
I'm not in a grocery store to make friends, I didn't walk into your gas station to chat with you about the weather, I want my stuff, you get your money, done!
Moving to another town or another state can sometimes have a wierd cultural effect on you. Maybe you're used to chatting with every clerk and every sales rep or whatever like they are your cousin (I don't talk to them either) and you move someplace where the woman behind the counter is NOT going to beam you a smile and say "Howdy! Nice day isn't it... blah blah blah.."
Or you're not used to it, and some grocery store checker (no offense
) starts chit chatting about nothing, you don't know what to say. You just kinda smile and roll your eyes and say "yeah, it HAS been hot. Yeah, the bulls DID lose big time." Then sigh, take what you came for and leave confused and a little irritated. This person might use the self-checker machine next time, even if it does take longer.
Anyway, it's all a cultural thing.
My advice is to just ignore people and only pay attention to them when you have to.
But watch out, you might be labeled "rude."