Oops, it doesn't look like 'park was forced to delete factual tweets about the environment cause they made the president mad happy day' is a national day..

Other days

Slime Day

Stress Awareness Day

Law Day

Lost Sock Memorial Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Gum Day

Cat Girl Day

Fiancee Day

Ask Out Your Crush Day

Pampering Day