Why do I keep old birthday cards from people who didn't even remember me this year?
CYNIC
You keep them as evidence that someone once cared, because this year's silence isn't quite damning enough.
STOIC
The cards are markers of transient moments, not permanent bonds. Keep them to learn detachment, not for the people.
ABSURD
You're curating a museum of affectionate ghosts who forgot the address. Next step: bake cakes for their shadows.