People in the Republic have embraced the EU in many ways and the standard of life has risen for the majority (yes issues still exist, but have nothing to do with the EU). Ireland in the past was a country that watched its children emigrate in order to survive ..... but the days of Paddy getting the boat are now long gone and its the other way around as Ireland is now very much a multi-cultural country that has learned to move on from the old days as it welcomes emigrants. There really is very little animosity towards the UK in the Republic as people are far too busy getting on with life and enjoying the benefits of the EU.
Northern Ireland has also benefited over the years and many there see the benefits of the EU hence the remain vote won out. The big question there is how long will the Unionists stay loyal if they are losing money and support. Boris is going to need deep pockets in order to keep his DUP mates happy as England Scotland and Wales will not be shy at coming forward looking for similar investment when the crash happens.
If (and its a big 'IF') push comes to shove, I can see a united Ireland will be on the cards with some sort of repatriation deal for the NI unionists to move to the UK mainland.