Northern Ireland

Since the attacks last spring in N. Ireland, I feel like they've constantly been in the news. I know the story of conflict and shit in the area, but I really want to know is why?

What does Northern Ireland produce that the U.K. wants so bad? Do they have good resources? Or is it just another area to tax to make money (which I'm sure it is). IMO, Ireland should be one and not split. There is no clear reason why the U.K. so badly wants it...

There is a significant population of protestants of English, and Scotch extraction living there who are remnants of wars from long ago.  They've been there, in some cases, for centuries.  The problem is the rest of Ireland is roman catholic, and if the English pulled out the protestants would become subject to a more restrictive, religiously influenced, regime.  Rights that British subjects take for granted, like some reproductive rights, would be stripped from them.