Oops, it doesn't look like 'go fuck yourself day' is a national day..

Other days

hoodie

Hoodie Day
gum

Gum Day
pick me

Pick Me Day
boba

Boba Day
self care

Self Care Day
cat girl

Cat Girl Day
boy friend

Boy Friend Day
slime

Slime Day
cursing

Cursing Day
kiss a brunette

Kiss A Brunette Day