Avoid stereotypes and generalizations, because you are likely to cause offense to the country you are visiting and shows your country in a negative way. all British people drink tea with biscuits at least once a day etc.
Just as not all Americans chew "spitting' tobacco" and wear cowboy hats there are cultural variations and you should never make an assumption asking is the safest thing to do.
Etiquette begins with some sensitivity to the perceptions and feelings of others and the intention not to offend.
Failing to thank and compliment a host, using a mobile phone in a theater, taking the last bit of a dish without offering it to others and many other examples of bad manners fall into this category.
All leading to a multitude of Kingdoms that to a point came to define the nations that exist today, most even shared rulers due to dynastic intermarriages for peace, power and territory.
The Napolionic wars started the downfall of many monarchies and by the time of the industrial revolution a push for normalization, social reforms and rule of law across boarders was generalized.
By the end of WWI the collapse of the remaining ultramarine empires was underway and a re-focus on the continent itself was unavoidable, especially after the devastation caused by the conflict and the influenza pandemic.
An example might be trying to discern whether someone is Irish Catholic or Anglo-Irish.All this coming together was intended to present a common front if not even to prepare for the next conflict, that ultimately originate in the reneging of promisees made (in the Tehran Conference and Yalta Conference, participated by The "Big Three"; Winston Churchill, Franklin D.Roosevelt and Joseph Stalin) to Stalin (Russia, USSR) and thwart its responsive advances West and in Asia (Japan, Korea), especially now that the "soviets" also had the atom bomb.When in doubt, avoid characterizing people according to a cultural identity.Make inquiries regarding identity carefully (if at all).Europe is very similar in its national structures (institutions, legal and political organizations, even the political inclinations tend to work in waves across the continent) and infrastructures (roads, rails and other mass transportation, police, departments, health and education, waste, water and energy).