No, I never got why its good luck.
But hey let's not let bare faced logic stop us reciting a clearly insane statement to people who have literally just been crapped on.
It's not literally rubbing it in as that would more unpleasant for the rubber inner ( unless you had latex gloves) but it's close.
Any way, it's just a card so hopefully no one will get too pissed off.
Amusing greetings card printed on 148mm x 148mm 380gsm card. Professionally printed. comes with envelope in cellophane wrapper. Shipped in hard backed envelope.