1.It’s fairly typical to take turns buying a round in Ireland.
It's considered courteous to go to the bar to bring back drinks for your entire table. Generally, everyone in the group should get up to offer up a round at some point whether you're asked to or not.
2.Combining seafood and cheese isn’t very popular in Italy.
In Italy, it's sometimes considered rude to ask for anything that isn't explicitly offered to you while dining out, according to Revealed Rome.
3.In Portugal, there’s no salt and pepper on your table for a reason.
It's OK to add a little extra salt or pepper to your plate as long as the condiments are already on the table. But according to Lonely Planet's "Portugal Travel Guide," asking a server to bring you salt and pepper is considered an offense to the chef's seasoning skills.
4.In Japan, slurping is considered a sign you enjoyed your meal.
In some countries like the US, it can be considered rude to make sounds when you chew or swallow your food. But in Japan, it's a way to show your server or chef that you enjoyed the meal, according to TripSavvy.