Oops, it doesn't look like 'nasty ass aftertaste in your mouth diet soda day' is a national day..

Other days

ruby

Ruby Day
tell ur crush you like them

Tell Ur Crush You Like Them Day
ask out your crush

Ask Out Your Crush Day
slime

Slime Day
tell a fairytale

Tell A Fairytale Day
get funky

Get Funky Day
kiss a brunette

Kiss A Brunette Day
brow

Brow Day
donate your hair

Donate Your Hair Day
buddy

Buddy Day