Oops, it doesn't look like 'start an argument just because day' is a national day..

Other days

hoodie

Hoodie Day
african immigrant and refugee hiv and hep awareness

African Immigrant And Refugee Hiv And Hep Awareness Day
boyfriend

Boyfriend Day
polyamory

Polyamory Day
self appreciation

Self Appreciation Day
blanket fort

Blanket Fort Day
reading

Reading Day
singles

Singles Day
unicorn

Unicorn Day
bounce

Bounce Day