Non national holidays should be added to holiday calendars. Things like valentine's day and Halloween. Sure those can be added with repeating events but holidays like Easter Sunday, mother's day and father's day are not on the same date every year, Easter doesn't even have to be in the same month. And I would argue that these holidays are more important to be on the calendar, everyone remembers what date Christmas is on but if someone forgets mother's day it's a problem.