Myths & Facts about Ireland.
St. Patrick: Fact; He was an historical figure, though not Irish. He was born in Wales, Scotland or Cumbria, England, depending on which source you believe: http://en.wikipedia.org/wiki/Saint_Patrick#St._Patrick_banishes_all_snakes_from_Ireland
Banished snakes from Ireland: Myth; there were never any snakes there in the first place! See the above link.
Shamrock: It only grows in Ireland & nowhere else; Myth; see this link. http://news.bbc.co.uk/1/hi/uk/3519116.stm
Poteen, moonshine: Fact; A potent alcohol made from potato peelings, once illegal. Can cause hallucinations (see below) http://en.wikipedia.org/wiki/Poit%C3%ADn
Leprechauns, little people, wee folk, fairies: Fact; can be seen after indulging in too much Poteen!
See also; http://www.sacred-texts.com/neu/yeats/fip/
Souvenir of Ireland: Fact; these exist in abundance, decorated with shamrocks, harps, etc. May have "an tseapain tir adheanta" stamped on the bottom. It's an enigmatic Gaelic (Irish) phrase which means " made in Japan!"
It's not that Pat & Bridie are wanting to deceive you, it's just good business sense!
The Luck of the Irish: Fact; mostly bad luck! Invaded by Vikings, Normans, oppressed by the English, famines, emigration, religious intolerance, etc. http://www.cracked.com/article_16017_6-reasons-irish-arent-so-lucky.html
See also "My Songs & Poems", "The Arabs, They Got All The Oil"
Guinness is good for you: Well, maybe; http://news.bbc.co.uk/1/hi/3266819.stm