I've always been curious as to why this is.
It's an Irish celebration that seems to have become a day for Americans to dress up in green and decorate everything with shamrock rather than a Religious Irish Holiday.
I'm not sure why this is. No offence to Americans but there seems to be a massive fad about everybody claiming to be Irish. More people claim have Irish blood in America than there are Irish people in Ireland, so there obviously a lot of people BS'ing.
I'm probably over reacting, but it just seems kinda odd.