A few years ago, I was in a small guest house in the middle of nowhere in China when this group of foreign tourists turned up. I won't identify their nationality in case I am accused of stereotyping. But just let me say I could speak their language (but didn't let on). I also speak Chinese.
The guest house, which is run by a lovely couple, does an evening meal at a very low fixed price. Cooked by the woman. No menu. You get what the family are having. Real Chinese home cooking. Utterly delicious
This group demanded "fish with no bones". (The tour leader spoke some basic Chinese). As it happened, the meal was fish based. Beer fish - a local speciality, With bones.
The woman lost the rag and went into a rant in Chinese while waving her cleaver with evil intent. She is normally as sweet as pie.
"If you want to eat XXXXland food, why have you come to China? Go back to XXXXland and eat your tasteless food! You can have fish with bones or nothing!"
The group grumbled and moaned and railed against the ignorance of the Chinese and the stupidity of of eating food with bones.
"The chicken in that other place had bones, too!"
Then it got nasty. They finished their meal and had several beers. When it came time to pay, they tried to claim that the set price for the meal included the beer which it certainly didn't. I heard them discussing their plan to demand free beer for revenge on bones.
They had seen my chatting with the couple in Chinese so they knew I spoke Chinese, but they were astonished when I used their language to tell them that they were well out of order and that beer is never included in the set price for a meal in any country including their country - one I have lived in.
They really were the rudest people.
Later that evening, after they had all crept off to bed knowing they had been rumbled, the couple told me that all the local tourist spots have a warning system. Most tourists follow well worn paths a la Lonely Planet. When one obnoxious group turns up, each hotel/guest house/restaurant passes on the information to the next. They knew this lot were coming before they got there, but can't afford to turn down business.
I just don't understand people who travel to other cultures but expect those cultures to follow their norms. Why bother going anywhere?