I use to have a routine with a friend where we paid close attention to the table manners of his wealthy upper class relatives. Then when they did something wrong we would point it out loudly as if it was the end of the world. Best was 3+ mistakes in a row. Bonus points if you can point out the mistake and add something like we are not in Belgium!

There is a wiki.

https://en.wikipedia.org/wiki/Eating_utensil_etiquette

Edit: The wiki on chopsticks has an etiquette section broken down by country.

https://en.wikipedia.org/wiki/Chopsticks#Chopstick_customs,_...

Yes! Hardly anyone knows it all, and even people who know the basics adjust their behavior based on the situation. Eating out with your high school buddies requires a different level of observance than the dinner at which your girlfriend is introducing you to her parents.

That's not really a coherent statement.

If people don't even know it, it's not part of the culture.