Oops, it doesn't look like 'do a grouch a favor day' is a national day..

Other days

lash

Lash Day
ask out your crush

Ask Out Your Crush Day
book

Book Day
buddy

Buddy Day
coffee

Coffee Day
tulip

Tulip Day
stud

Stud Day
lumpy rug

Lumpy Rug Day
nae nae

Nae Nae Day
fiancee

Fiancee Day