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

Other days

promposal

Promposal Day
lisp

Lisp Day
polyamory

Polyamory Day
nae nae

Nae Nae Day
reading

Reading Day
girl friend

Girl Friend Day
boyfriend

Boyfriend Day
fiancee

Fiancee Day
carpenters

Carpenters Day
ormille

Ormille Day