When I went down to Atlanta to visit my brother and his family two years ago, I went shopping at a mall with my sister-in-law. It was Thanksgiving weekend, which is absolutely insane up here in the Detroit area. In Atlanta, it wasn't nearly as hectic. There were lots of people shopping, but no one was dashing around, sighing impatiently, or generally being rude. The people were a lot friendlier too. I was shocked at first when my sister-in-law started up conversations with people in line with us, or sitting next to us in the food court. Up here, generally the only conversations I get into with strangers while shopping tend to be people complaining about something while they're waiting in line. When the shock wore off, I decided that it was cool.
Messy Buu, if you fired and blacklisted all the people like that, the fast food industry among others would collapse. If you're working as a cashier or something like that at a grocery or in the fast food industry, you're doing it because (a) you're a teenager or a college kid (

you're retired and need to get out of the house (or need the money) (c) you're working a second job or (d) because you can't do anything else. Type A is transitory and the turnover of these kids is high, and they're only there for the paycheck. Type B is less transitory, but they don't really want to be there either except that it's better than staying at home. Type C is already frazzled and possibly feeling bitter. Do we need to go over Type D, or should I just refer you to the articles on this site about welfare?
I agree with Jeremy. The best thing that you can do is provide a good example, and keep your irritation from ruining your day. Bad moods or positive attitudes affect the people you come in contact with. It's something that I could stand to remember more often.