(I manage a small academic IT department. Sometimes I deal with customers directly. This was one of those times.)

Person: “Could you please fix this web app that stopped running?”
Me: [investigates] “Sorry, no. It’s a Flash applet, so I can’t change the contents. It’s not running because the security model in Flash changed to disallow the things your applet is doing.”
Person: “But we paid someone to write it!”
Me: “Ok. Talk to your vendor, then.”
Person: “We can’t, we had it written in 2003. We really need it to work.”
Me: “Maybe it’s an easy fix. Do you have the source code?”
Person: “I don’t.”
Me: “Sorry, I can’t help you then.”
Person: “How come you fixed a broken link a while ago but won’t fix this?”
Me: “Because that was a completely different issue. I literally can’t help with this one.”
Person: “I shall complain to my supervisor that you are unwilling to help!”
Me: HEAD ASPLODE

It’s a quietish night and there are about four or five tabs in my theater and I’ve gone to drop off the bills 45 minutes before the movie ends as per training. After about ten minutes I go pick up most of the tabs and all but two of the groups have left cards or cash to pay as i silently make a round to close the tabs and leave change, all while trying not to disturb the movie. Its understandable that sometimes people are so absorbed into the film they don’t want to stop and dig through their wallet in the dark to pay. Anyway I have two tabs left to close out and when dropping off the completed checks I do a quick round while ducked down out of view to see if any of the other guests are ready to pay. The second to last tab is ready and I close it out. I get a really nasty look from my final table as I pass by to check on them but say nothing and still squat when i walk to stay out of the view of the movie. After closing the second to last tab I drop it back off and once again check on my final table one last time, not even bothering to go into the row but just sort of nose raising and squinting from the aisle to see if they were ready. I got more nasty glances.
As per rule, I never go back more than three times to check on a payment. Its rude to interrupt more than that and at that point I can also assume some people prefer to wait until the movie ends and/or the lights come up to read the bill. Usually I have no problems at all and people are generally thankful I am willing to wait on them after the fact or offer my flashlight if they need it to see. But this family seemed to feel differently about it.
I had no other duties at the time so I stood on the other side of the ramp divider that led up to the seats out of sight and silently watched the tale end of the film. None of the guests could see I was there until they began to leave and I bid them farewell.
Well, my final group stands up and hastily tries to make a break for the emergency exit instead of the regular door where I stood. They didn’t see me but I could see them trying to walk out on the tab. I kindly called to them and said the fire exit was for emergencies only and directed them to the correct exit. I inquired about their bill and they said that they left the money on the table. I ran to check but it was obvious they were lying. I tried to play along and ask if it could have fallen and took my flashlight out to look around. Not beating around the bush, they scoffed and just handed me the actual payment in exact change. (no tip-surprise surprise!) I closed them out and the whole time kept a smile on my face. Livid, the lead lady of the group asked to speak to my manager. I obliged but overheard every word from my server station as she yelled that I was racist to black people, ran and checked on them “like twelve times”, I ruined the entire movie by getting in the way, and I needed to be fired. Extreme emphasis was on her racism argument. My manager apologized and simply assured them I was not racist in any way whatsoever and he was sure of it. The whole time I had to hide my face and avoid snickering. The group left unhappy.
My manager then approached me and heard my side of the story. I told him I only checked on them three times like I always do, they tried to run out on a triple dollar figure tab though the fire exit, and I stopped them kindly and made them pay. He just nodded, told me I did a good job and walked away.
The reason my manager knew I wasn’t racist?
My husband is black. I bring him around all the time and the whole company knows. Besides, Ive always prided myself on treating all my guest in the same, kind manner. At least two other tables in the theater were black as well and had already complimented my service and tipped well.

I work in a popular retail chain that caters to the teen market, but adults tend to shop here, too. I’m used to rude behavior from teenagers, but when it comes from adults it’s somehow worse because you expect better.

Two women and their daughters come in five minutes prior to closing time. The associates are cleaning up the store and, as I’m the closing manager of that night, I kindly welcome the customers and tell them we will be closing in five minutes.

Woman: “You don’t think I know you close in five minutes? I got a watch. You think I don’t know how to tell time? If you’re unhappy working here, you need to get yo ‘edumacation’ so that you can get a better job.”

Me: “Ma’am, I’m currently in school getting my education and working here while I do so, thank you very much.”

This customer and her friend start purposely messing up the clothing racks and one of them calls me a b**** loudly enough that I can hear it.

Me: “Ma’am, I approached you in a respectful manner and your behavior is unnecessary. You have no right to tell me to get an education when I can keep my composure and speak to you in full sentences while you have to resort to cuss words.”

Their daughters look embarrassed and one of them even tells her mom:

Daughter: “Mom, all she said was that the store is closing in five minutes. Let’s go.”

The woman smacked her lips at me, called me a b**** one more time, and messed up one more rack as they exited the store. All I could do was laugh. You know it’s bad when your daughters are embarrassed to be seen out in public with you.

I manage a small family bakery- our specialty is old fashioned hand made pie. The 3 days before Thanksgiving are our “Black Days” 3 days of 12 hours and lines out the door all day. The whole building is tiny and we make/bake as much as we can as fast as we can- so everything is first come first server and we do not take orders.
This makes for some interesting phone calls
My standard polite response is
“I am sorry ma’am/ we do not take orders or hold pies- we do not have the space to store them. You have to come stand in line, it moves fast and you get a chance to make some new friends”
Phone calls do not get to me unless the customer will not take no for an answer- since my girls know that I am not the most polite person or suffer fools

Cust #1 “You have to take my order, I want 3 pies and I refuse to stand in your long line, don’t you know rich people hate to stand in line”
Me: if you are that rich I am sure you have an assistant or maid who could do it for you
Cust # 2 “You know your lines are too long- who would stand in line for pie? Take my order or I will never come there again”
Me: Great have a nice day- the 100 other people in line will have more pie
Cust #3 “The owner always takes my order, he does it all the time and you have to do now- I am too important to stand in line”
Me: Sir- our original owner died last year, thank you for the reminder that he never cared how important people were just that they got the best pie

My favorite by far was a few years ago
Cust- This is JaZe and Beyonce tour manager- they are in town for Thanksgiving with her parents and the “Star” wants to surprise her mom with a pie”
(B’s mom is a very nice lady who does in fact come in for pie during the year)
Me: “I am sorry sir we do not take orders or hold pies- we do not have the space to store them. You have to come stand in line, it moves fast and you get a chance to make some new friends”
Cust- You don’t understand, these are STARS! STARS do not stand in line- STARS get special treatment! STARS get whatever they want, when they want! And these STARS want some of your pie! do you know what they could do for your business?
Me: Well the STARS should have thought ahead and send an assistant to stand in line early this morning. Thank you but we already make as much as we can we really don’t need any endorsements. Please tell Ms B’s mom that T the manager said hello and we will see her later in the year. <click>

This is one of the far and few stories where I (the customer) actually kept their cool when they could have gone off. My friend and I went to a very popular department store to look at dresses for a wedding I am attending next month. We found the perfect dress but I had to order a bigger size since they did not have anymore there. We go to check out and the cashier begins by smiling and telling me she will look up the biggest sizes they have .. umm okay thanks .. then after that transaction has been completed, she fussed at me for choosing the email receipt option instead of having it printed out, and then goes through and makes the receipt print out to give to me. I was also purchasing another outfit and a pair of spanx/shapewear. She proceeds to ask if I tried it on bc she doesn’t think it stretches THAT far and tries to demonstrate that it’s not very stretchy … at this point I’m extremely confused. Is she trying to say maybe the material is not good? Is she trying to be helpful? Or is she just blatantly saying that I’m too big to fit in these clothes? (I’m 5-1 curvy and am a size 10-12). I smiled and just made it through the transaction without getting annoyed but I couldn’t help but think she was so rude.