This isn't luck at all, but more of an attitiude, a positive look at a bad situation.
The Irish didn't survive a potato famine, and being treated as 3rd class citizens upon their arrival to the U.S. (til the mid-late 1900's)by not having a positive outlook and a great sense of humor!
Mary-"I was just wearing my new shoes today when I stepped in a HUGE cow shit"
Michael-"Well then, tis a LUCKY thing you were wearing shoes!"
Mary-"Yea, Luck of the Irish"
Bad luck... People think the irish are lucky. They are wrong.
The Irish drink because they are cursed with the luck of the irish.