Trying the unthinkable...

You know when you're at the grocery store and you slide your credit card to pay? The little screen posts the amount and asks, "Is this amount OK"? I've always wondered what would happen if I wasn't OK with the price and pressed NO? I wonder if I can get a cheaper price for my groceries. Almost as if I'm able to negotiate with the credit card terminal. On another note, have you ever called At&t, and the customer service representative was wonderful and at the end she asks you to rate her 1-5 (5 being the best) based on how well she helped you? I've always wanted to tell her 1 to see how she responds to that but I don't have the guts to do it. Also when going to a restaurant, and the waiter tells you to tell him when to stop putting the pepper on your salad, I've always wanted to wait an excruciatingly long time before telling him to stop just to make it awkward.