Oops, it doesn't look like 'nightmare to this day' is a national day..

Other days

boba

Boba Day
youth

Youth Day
cursing

Cursing Day
ormille

Ormille Day
bow tie

Bow Tie Day
ride the wind

Ride The Wind Day
stud

Stud Day
boy friend

Boy Friend Day
lisp

Lisp Day
donate your hair

Donate Your Hair Day