"The UK traditionally had its largest trade surplus with any country in the World with Ireland. "
That is typical of Empires and Colonies. Acknowledging that I may be biased by my growing up with Irish-Americans. The Irish immigrants to America were typically those with the most hate for England.  

Dick Bolger was one of my grade school classmates. He lived at the end of the block. His father would not allow the words England or English to be uttered in his house.

I think I have a feel for it. I once expounded to my good friend and co-worker Doug Kennedy on the similarities of Ireland and Sicily. Both islands with internal squabbles. Both subjugated for centuries by foreign powers. Both with internal revolutionary/criminal secret societies. There was more but I don't have a Guiness in front of me to stimulate thought.  (Ireland has prettier girls, though)