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

Other days

blanket fort

Blanket Fort Day
promposal

Promposal Day
offer

Offer Day
tell a fairytale

Tell A Fairytale Day
martini

Martini Day
boyfriend

Boyfriend Day
self appreciation

Self Appreciation Day
boba

Boba Day
bow tie

Bow Tie Day
coffee

Coffee Day