Bah! Humbug! Another Day, another dollar..what is it this time? Fathers' Day? Flag Day? Piffle! These Days are ersatz. So is Presidents' Day, MLK Day, Washington's Birthday, Armed Forces Day and most of the rest. The secular Days that resonate are, in order of importance, April Fools' Day (wit and invention), Guy Fawkes' Night (bonfires and explosions), Halloween (mischief and scariness) and Valentine's Day (let osculation thrive). Remembrance Day (poppies and an empty tomb) stands alone. I don't think Memorial Day bears the same weight. Thanksgiving pings in my head, but not yet my heart.
Cards, poems and presents are good, providing they're homemade and the exception not the rule. Oh for the courage to apply that to Christmas!
But the rightful God of secular Days is Loki.