Historically, America will adopt any immigrant group's holiday if it involves food and definitely alcohol. Or they will turn it into food and drinking. St. Patrick's day is actually a fairly solemn day in Ireland. The Irish turnt up in America for it years ago as a flex. Same with Cinco de Mayo. I was told by Mexican friends once its bigger in California than it is in Mexico.
England adopted Halloween from us. The big surprise is that Germans are one of the biggest immigrant groups in American history but Oktoberfest is not big in America which is a bit of a head scratcher.
Anyway, office parties is where I 'celebrate' most holidays. I've gone to Halloween parties if its going to be lit. I take the holidays on a case by case basis. The exceptions are Columbus day, which I refuse to observe. And I'll gladly accept the 4th of July as a paid holiday but I'll be damned if I'm going to some parade waving a flag. I don't do the 'Never forget' thingy on social media for 911 or December 7th either.