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

Other days

china

China Day
nae nae

Nae Nae Day
ride the wind

Ride The Wind Day
polyamory

Polyamory Day
buddy

Buddy Day
self appreciation

Self Appreciation Day
blanket fort

Blanket Fort Day
law

Law Day
promposal

Promposal Day
reading

Reading Day