Make sure to get your geography right. Ireland is famous for their beer, rowdy citizens, and being an independent country. One sure fire way to piss of a citizen of Ireland is to refer to Ireland as part of the United Kingdom.
…It hasn’t been for quite some time. Northern Ireland is still a part of the British Isles, though. In fact, tensions between Northern Ireland and Ireland have been tumultuous in the past. Adding fuel to the flame will make you commit a cultural faux pas and probably land you in an awkward situation.