<human>: Give me the gist of the text in a nutshell

I went to the store to get some trash bags for the office today. When I was trying to pay for the bags, before I do anything, the clerk started leaning over the bar code scanner, looking at the card scanner as I swiped my card. When the price of the purchase and buttons, "Approve" and "Decline" appeared on the screen, before I could do anything that made since, she reached over and hit the red button with an X on it instead of the green one and said, "Red stands for Credit." Now, as you can expect, the word "Canceled" popped up on the screen. So I told the clerk that red stands for cancel (as politely as one can after witnessing such an act). She ignored me. So, clearly, the most reasonable thing to do when something doesn't work, is to do the exact same thing again thinking that you were right the first time, something just went wrong with the computer. On the third time I swiped my card, she started looking at the computer, trying to find the problem there. So when the "Approve" button popped up on the screen, I quickly hit it before she could turn around and show me how helpful a clerk she could be some more. So when the receipt magically sprayed out of the machine, she said "You're welcome." What blatantly stupid people have you come across that makes you wonder how we survived this long?
<bot>: Went to buy trash bags, ended up learning that the movie "Clerks" is surprising accurate to the real ones.