There are only a couple of real “holidays”. Christmas, Easter, Thanksgiving, and New Years. The rest are just excuses to, as you said, get hammered drunk or to have a day off.
Halloween, St. Patties day, Cinco de Mayo, etc. are all just random days off that people get to do something ‘out of the ordinary’ (take a day off mid-week for example or get especially drunk). It’s all dumb in my opinion.
I HATE Halloween. Why the hell do adults dress up and parade around the office building? It’s f’in GAY. I had to be Charlie Brown last year for the department thing. The year before that I was the father in “The Adams Family”. So f’in stupid. I’d say no but then I’d get the ‘you’re not a team player’ crybaby shit so I just suck it up.