What is/was this war between england and Ireland about?

So I went to a sleepaway camp for adults with disabilities this summer that get counselors from England, Ireland, and other parts of Europe to run it... they were ALL really into me... the English were into me because I was"REALLY"into England and had always wanted to visit there some time, so I as able to ask all my questions about it then... plus they were interested where"i"origanally came from too!

But the one from Ireland was CRAZY about me..."BUT"what my mom told me England and Ireland afterwards STUNNED me because they... well they"DID"argue a little there too but not about their NATIONS really!

Anyway that they recently had a big war and I was wondering how it was even possible for the camp to get counselors from BOTH countries to run it if they clash with each other?

I mean I DID see it myself and was wondering about it because the one from England DID argue a LITTLE with the irish counselor about stuff but nothing too severe but either way THEY seemed to be best friends, so I was very surprised to hear from people that they really"DON'T"get along?

Do you suppose they just knew to keep their politics and personal problems of THEIR country aside and still TRY to act professionally at work?

I mean don't get me wrong they"DID"argue at times there!

What is/was this war between england and Ireland about?
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