"Before I came to America, I'd never seen a green bagel." She says. "For Irish-Americans, they think of dying food green, they think everything is happy. But really, in terms of the famine, this is very sad imagery."

Of course, Americans have long embraced St. Patrick's Day traditions that might bemuse the folks back in Ireland, where festivities are a lot more subdued, Kinealy notes.

For instance, St. Paddy's Day Parades? Those originated here in the late 1700s. (George Washington was known to give his Irish soldiers the day off so they could join the celebrations, she says.)

And that quintessential dish of the holiday, corned beef — it may be delicious, but it's most definitely not Irish.

As Smithsonian.com noted last year, in Gaelic Ireland, cows were a symbol of wealth and a sacred animal, kept more for their milk than their meat – which was only consumed once an animals' milking days were over. In the Irish diet, meat meant pork. It wasn't until Britain conquered most of Ireland that Irish "corned beef" came into existence — to satisfy the beef-loving English.

"Ironically, the ones producing the corned beef, the Irish people, could not afford beef or corned beef for themselves," Smithsonian notes.

Funny enough, the Irish didn't learn to love corned beef until coming to America – where they picked up the taste from their Jewish neighbors in the urban melting pot of New York City.

But these days, even the Irish back in the homeland have to come to accept this Irish-American dietary quirk, Kinealy says. As tourist season revs up and Americans head to the Emerald Isle to celebrate St. Paddy's Day, "a lot of pubs in Ireland will offer corned beef because they know the tourists like it. It's come full circle."

Copyright 2014 NPR.