A man came up to my till with a stack of the Economist. All but throwing them at me, the following conversation ensues:
Customer: “You need to be stocking [the magazine] on the front shelf here. I brought some for you to stock.”
Me: “Sir, the space on our register aisle is paid space that was purchased by the magazines you see. It’s not up to me to decide what to stock, so I can’t put them here.”
Customer: [Getting angry] “What do you mean? You need to change that! These need to be up front! I’ll stock them for you.”
Me: “You could be removed from our store for rearranging our stock like that. Tell you what–I’ll stock them.”
Customer: “Wait, really?”
Me: “Yes.” [I grab the magazines and put them on a cart of other materials to be put back in their sections] “I’m stocking them back to where they go, because they don’t go up here. Anything else?”
I wrapped up the sale, and thanked him for coming in. I have not seen him since.

(I work at a movie theater/restaurant with a very strict no cell phone policy. I’d noticed that a woman has been standing outside of one of our theaters for quite some time, talking to someone on the phone. There’s nothing wrong in her doing this, seeing as she’s not in the theater. I return later with a tray full of food to deliver to the theater, and the woman is still on the phone. As I approach, she flags me down.)
Woman: Sir, hello, excuse me! Could you tell him about your cell phone policy? Here, I’ll put him on speaker phone. (She taps the speaker phone button and holds the phone in front of me.)
Me: Oh, um… Well, we have a very strict no cell phones policy during showtime, you’ll receive a warning from a manager and then you’ll be thrown out without a refund if you are a repeat offender.
Another employee: It’s no tolerance.
Me: Yeah…
(The lady returned to her phone call, clearly angry at who she was talking to, and promptly hung up on him. She apologized and thanked the two of us for helping.)

(I’m the producer, which means I make the gelato in the back of the store and don’t interact with the customers. However, all that separates us is a sheet of glass, and I can easily communicate with my co-workers. We get mostly tourists, and they almost always order quickly and leave once they get their gelato.)

(A family of around eight of Middle Eastern descent walks in and converses with my manager, who’s serving them. All of a sudden, he looks back at me, his eyes light up, and he walks over towards the back to say loudly)

Manager: “No, sir, we don’t have alcoholic ice cream. And no, we can’t add alcohol to the ice cream if you go buy some. And no, we aren’t changing that.”

Me: *organizing a stack of box fans*
Customer: Excuse me, where are your fans?
Me: They are right here.
Customer: Oh, thanks.
Manager: *laughs from around the corner* Did that just happen?
Me: Yeah, wow.

I do food service at a local theme park. I had just got off of my break, and was walking back to the stand I was scheduled for that day. It’s July 4th, and had been raining slightly. A guest walks up to me with an umbrella opened. It’s 2:30 in the afternoon.
Customer: “Excuse me.”
Me: “Yes, how can I help you?”
Customer: “Where is the exit?”
We are literally standing in front of the main gate.
Me: “Umm, actually sir, it’s right here.”
Customer: “Oh, thank you. I rain is so bad, I just need to get out of it.”