Oops, it doesn't look like 'british tea day' is a national day..

Other days

bonang

Bonang Day
boyfriend

Boyfriend Day
bow tie

Bow Tie Day
eat what you want

Eat What You Want Day
mean girls

Mean Girls Day
nae nae

Nae Nae Day
slime

Slime Day
coffee

Coffee Day
blanket fort

Blanket Fort Day
tulip

Tulip Day