This is a poem I wrote for a friend when I was in school. The last two lines are inspired from an Archies card.
All days come but once in annum,
Amongst them all very special are few,
Amongst the few you love the most is one,
The day when the world got you.
You celebrate the day you're born
And want your chums to be near.
I regret that I left you lorn,
Hope you pardon me, O dear!
Shamelessly I wish you, 'A belated very happy birthday'.
Though I know, now it is very late;
But I swear, I didn't forget your birthday
I just forgot the date.