Maybe Ireland shouldn't be offended by tourists who think it's in the UK
Like you, I get frustrated when people fail to understand the difference between Ireland and the UK.
It's a sign of ignorance, and shows total disrespect for over 100 years of history and denies people their own identity.
In the time I've been here, I've lost count of the number of Irish people who have told me that their "favourite part of England is Wales".
I've also had conversations with people in Wicklow who reckon they can see England from the coastline (you can't - it's Wales), and let's not start on the things I've heard said about the Isle of Man and Guernsey (these are barely in the UK, and definitely not English).
It may seem pedantic to pick people up for not understanding the intricacies of a very complicated political set-up in their neighbouring country. But to people in Wales, this is a another case of their heritage and identity being denied by clueless foreigners.
I'm not perfect here. I'm pretty sure I couldn't draw a map of Europe without getting most of it wrong. Even so, ignorance isn't something to be proud of, and it's courteous to learn about the place you're visiting.
However, before getting angry at clueless Americans who don't know there is a political border at Newry, perhaps Ireland ought to check it knows its own neighbours first.