This, ladies and gentlemen is why there may be a united Ireland in our lifetime.
The UK didn't get, as you put it so eloquently @IvorTheEngineDriver, "lumbered with NI".
The UK could have removed themselves, lock stock and barrel from the island of Ireland and then NONE of the troubles or anything else would have happened. The UK (for that read Westminster or even in some situations just England) wanted to own all of the island of Ireland.
It's amazing how, when the British colonised countries, they left a holy mess in their wake - see The Troubles in NI, and India/Pakistan and that has worked out well hasn't it!
I was never staunchly nationalist, Republican or any flavour in between. I was very much a live and let live person.
However, as I get older, I can see why the Easter Rising happened, why the Troubles happened and I find it interesting that there was more progress made with Westminster when there was a Labour government in charge than for the decades of Conservative "leadership" there has been since the late 1970's.