Two came to mind yesterday :
England is a self-defined Christian kingdom,
with a National (and royal) Church like the Nordic countries -
but very few Christian festivals (only Christmas and Easter) are celebrated,
and few inhabitants would have known that yesterday was Ascension Day.
France is self-definedly atheist,
but it has public holidays for Ascension, Whitsun and the Assumption of the Virgin Mary,
as well as Christmas and Easter.
Moreover, most French calendars tell you which saint's day it is...
Go figure !