Two Irishmen, two scots, and two Englishmen are shipwrecked on an island.

Within one week the two Irishmen have built a still to make whisky.

Within two weeks the two Scots have built a pub to sell the whisky in,

And after four weeks the two Englishmen are still not talking to one another as they've not been properly introduced.
My Grandad told me this one years ago.