Oops, it doesn't look like 'Office Wore Plaid On day' is a national day..

Other days

youth

Youth Day
brow

Brow Day
hiv awareness

Hiv Awareness Day
boba

Boba Day
law

Law Day
polyamory

Polyamory Day
buddy

Buddy Day
stress awareness

Stress Awareness Day
china

China Day
cat girl

Cat Girl Day