Customers in my store had a sense of entitlement - they tried to get as much as they could from you beyond what is available. I found this ironic because it was in a hard-pressed area. However, this also meant you get some crafty customers as well who constantly tried to cheat the system - so you need to have your wits about you. Having said that, you get to recognise the regulars, and they can be a joy to serve.
An unnecessarily impatient customer, the know-it-all, the "customer is always right", and the clueless customer are the most annoying.
Be polite, friendly, and understand that there's only so much we can do. We will go out of our way for a friendly and understanding customer - but a rude customer won't get much beyond a "nope, not in stock." if it's not on the shelf.
