Oops, it doesn't look like 'chair invasion day' is a national day..

Other days

one

One Day
hoodie

Hoodie Day
first love

First Love Day
cat girl

Cat Girl Day
kale

Kale Day
nae nae

Nae Nae Day
boba

Boba Day
lumpy rug

Lumpy Rug Day
aloxolt

Aloxolt Day
ruby

Ruby Day