You go to a fast food drive through and they screw up your order. If you, god forbid, point out their mistake, you are met with rolling eyes and yet another sigh of disdain. These days you are really lucky to get an insincere "Sorry".
Look, I understand you have a crappy job, I have had them too, but it's not my fault that you are having a sh*t day. You are paid to smile and be nice to customers. Hence the customer service aspect of your customer service based role. So just do it. It's only for a few hours.
So join in the rant, tell me about your crappest customer service experience. It just seems that customer service is pretty much non existent these days. Here you go, these are the clothes I don't want. Would you be a dear and hang them back up for me? Not bloody likely.