My ex-BIL once visited a local hamburger chain fairly late at night after clubbing. This chain was known for being open 24 hours, so the lateness of the hour wasn't to blame for what happened next ... he ordered a burger, and the waitress pulled out a bag of buns. Every single bun was BRIGHT GREEN with mould. He waited for her to notice, and when he realized in horror that she was about to use one of the buns anyway, he pointed out the issue. Her response: "Oh. Did you want me to open another bag?" Him: "No, thanks. I think I'll eat somewhere else."