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

Other days

lisp

Lisp Day
latina equal pay

Latina Equal Pay Day
slime

Slime Day
tell a fairytale

Tell A Fairytale Day
boyfriend

Boyfriend Day
brow

Brow Day
cat girl

Cat Girl Day
gallery

Gallery Day
one

One Day
gum

Gum Day