This may not matter to you, and that’s fine for it doesn’t matter to me either, but if you are interested - and I’ve said this many times before:
There’s no Patty’s Day in Ireland
There’s no St. Patty’s Day in Ireland
There’s no St. Pat’s (Day) in Ireland
There is only St Patrick’s Day, very commonly called Paddy’s Day. That’s it.
The reason I’m saying it again is that in the 4 and a half years since I’ve left the U.S. and returned to Ireland I have found it hilarious every year watching thousands of Irish people (in Ireland) discover, primarily through the medium of twitter, and get apoplectic that, their Irish-American cousins are prone to saying Patty in the context of our national holiday and saint.
Honestly - it bothers people
See here: Paddy, Not Patty
Someone even went and made a website.