My first issue with the celebration of St. Patrick's Day is an issue I have with the celebration of any saint's feast day- Catholics were and are persecuted in America for believing in and praying to saints. Other denominations believe praying to saints in lieu of God is heretical and blasphemous. Catholics would get beaten up because of it. So why would anyone and everyone celebrate saints' feast days? To get drunk or presents or drunk. Oh, you like beer but don't believe in saints? By all means, celebrate! (I am very well aware of the fact that many Irish are Protestant and therefore don't believe in saints but probably celebrate today as a heritage day- not a saint day per say.)
America has a long history of hating the shit out of Irish immigrants. Yes many, many Americans have Irish ancestry and that's cool, great even. However, there are probably just as many German Americans and Italian Americans as there are Irish Americans but we don't go around celebrating Saint Boniface or Saint Joseph to the same degree. And those groups weren't ostracized like the Irish. Is it simply because the Irish were Catholic? The Italians are known to be very Catholic. So why weren't they kicked around? Is it because they drink beer? The Germans drink beer. So bring on June 5th and let's get drunk and wear green for the Christmas trees St. Boniface is said to have invented. Oh, and just so you know- St. Patrick's color is blue. Not green. So why celebrate a day that remembers a people the Americans historically beat the shit out of?
Also, I find it horribly offensive and rude that the heritage day of Ireland is commemorated by drunkenness. Alcoholism is a real problem in the economically depressed Ireland. But by all means, honor Ireland by pissing your pants from being too drunk.

On the other hand, to those who take their ancestry seriously, Happy Saint Patrick's Day. May you enjoy your corned beef and your Guinness. Sincerely.