Oops, it doesn't look like 'society of stupid people have a nice day' is a national day..

Other days

Gum Day

Pumpkin Day

Donate Your Hair Day

Chocolate Milkshake Day

Aloxolt Day

Slime Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Nail Polish Day

Unicorn Day

Tell Ur Crush You Like Them Day