Oops, it doesn't look like 'trends in a single day' is a national day..

Other days

fiancee

Fiancee Day

singles

Singles Day

nae nae

Nae Nae Day

embarrass your best friend

Embarrass Your Best Friend Day

boy friend

Boy Friend Day

tell ur crush you like them

Tell Ur Crush You Like Them Day

lost sock memorial

Lost Sock Memorial Day

comfy

Comfy Day

donate your hair

Donate Your Hair Day

Me Day