Holiday Suggestions

So I hardly ever play with the calendar. Does the holiday I set in one household stay the same for all households? Is the calendar universal? I totally avoid changing the calendar because I was under the impression that I would have to do that for every family, adding on an extra year of work to get this save started.

And for me, a IRL person who hates holidays, I would probably remove almost all of it and create some fun things that make me want to take my sims out on the town.