Oops, it doesn't look like 'casual day' is a national day..

Other days

aloxolt

Aloxolt Day
self appreciation

Self Appreciation Day
tell a fairytale

Tell A Fairytale Day
emoji

Emoji Day
boy friend

Boy Friend Day
law

Law Day
ruby

Ruby Day
self care

Self Care Day
ride the wind

Ride The Wind Day
bonang

Bonang Day