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

Other days

buddy

Buddy Day
stud

Stud Day
stress awareness

Stress Awareness Day
hoodie

Hoodie Day
aloxolt

Aloxolt Day
my little pony

My Little Pony Day
one

One Day
youth

Youth Day
hiv awareness

Hiv Awareness Day
lisp

Lisp Day