Customer comes in with a 50% off any one regular priced coupon.
Customer: I'd like to use this coupon for each of my items.
Me: I'm sorry. You can't do that, because you can only use this coupon once.
Customer: That's illogical! Other cashiers have done it for me. This is wasting my time. That means I'd have to come again tomorrow. I should have just gone to the location in [nearby place].
Me: It's against company policy.
And from here, the customer starts thinking she knows better than me how the company works and tells me that this is not how the company works. So I explain to her that it's right on the first line of the coupon and she hits me with this:
"I know what the coupon says, but that's not how it works."
Since the customer came with their husband, I even gave them two items off, one for her, and one for her husband, and she was still pissy.