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

Other days

lisp

Lisp Day
buddy

Buddy Day
hoodie

Hoodie Day
tulip

Tulip Day
eat what you want

Eat What You Want Day
offer

Offer Day
ask out your crush

Ask Out Your Crush Day
stud

Stud Day
bubble bath

Bubble Bath Day
cursing

Cursing Day