Oops, it doesn't look like 'Gf Or Sister day' is a national day..

Other days

buddy

Buddy Day
martini

Martini Day
kiss a ginger

Kiss A Ginger Day
self appreciation

Self Appreciation Day
lumpy rug

Lumpy Rug Day
boba

Boba Day
carpenters

Carpenters Day
lisp

Lisp Day
singles

Singles Day
comfy

Comfy Day