My job isn't crap, I actually enjoy it surprisingly enough, considering it's working in a supermarket with most of my time spent reducing prices on short-life stock (and throwing the out-of-date stuff away). But there are some customers I get annoyed with easily. Most of the people I deal with are friendly and polite, and I'm happy to help them (and they usually thank me and are happy enough with the service received). I've even got a couple of customers who are regulars of our store, and usually have a bit of a chat with me while I'm working (that is, they do the talking, I listen and comment while focusing mainly on the job at hand). But then, it appears that our supermarket chain seems to attract decent people (I work at Waitrose, where most of the staff and customers are pretty good, whereas whenever I shop in, say, Tesco, the staff are incompetent or just don't give a flying fuck

).
Nevertheless, sometimes there's the odd customer who I hate dealing with. Once, near Christmas last year, I was reducing a load of meat, and we work by section - meaning I'd do, say, pork first, then move onto lamb, then fish, and so on. A woman came up to me asking if I was going to be reducing a load of sausages - I told her that we work by section, politely, and said that I may be doing the sausages but it would depend on what else needed doing and what my manager told me to do. So she walks away, and I carry on with the job. Before I get around to the sausages, my manager asked me to do another task, which meant I wouldn't have time to reduce any sausages before we closed - so right before closing time, the woman comes back (she'd literally hung around in the store for around an hour just walking around waiting for me to reduce the sausages for the next day's date, which would be maybe 50p off each pack

), and asks me if I'm reducing the sausages now. I politely explained that I couldn't as I hadn't the time, and I'd been asked to do a different job - so the woman starts getting all mouthy, complaining that I should have told her that an hour ago (bear in mind that I'd answered her original question, and had no way of knowing beforehand how long the job would take), and makes out that it was my fault for not telling her in the first place, even though I did.
Seriously, I wanted to give this woman a right good bollocking, which is an English slang term for basically having a go at her and calling her an idiot and whatnot, for you non-Brits out there. Sadly, I couldn't do that because if she'd made a complaint, she'd have the upper ground, and I would be liable (and there's no way in hell I'm going to lose my job willingly over something stupid like that). So I just apologised and proceeded to carry on with my job, ignoring her inane moaning. She never did get the reduced sausages from me, either xD.
Oh, and we also have a guy who comes in regularly, a pretty old Indian/Pakistani guy who can barely speak English and makes a habit of seeking me out to get things reduced. I'm not being racist here, just stating facts - I simply can't understand half of what he says. He makes a habit out of looking on the shelves, checking for stock that's going out of date today that we've missed in our 'gathering up', and bringing it to me and the rest of the Operations team to get it reduced. He then tries to dictate what we should reduce it to (usually along the lines of 10p for everything, no matter how much it originally costs). In the end I just got fed up enough to call him out on it, though I was careful with my choice of words so if he complained I wouldn't be liable for offending a customer... hell, I actually saw the guy near our other branch in my city, when I was doing some luxury item shopping - fortunately he didn't spot me. It's bad enough dealing with the guy at work, I don't want to deal with him on my days off as well...