Why do people keep receipts they will never look at again?
Paper is cheap. Certainty is not.
People keep receipts not because they expect to use them but because receipts protect certainty. The hidden mechanism is Borrowed Certainty. A receipt quietly promises that if something goes wrong, proof already exists.
A receipt is one of the least interesting objects people own.
It is folded, forgotten, and eventually buried inside a wallet or drawer.
However, throwing it away immediately often feels uncomfortable. The hidden mechanism is Borrowed Certainty. The paper itself is worthless, yet it contains something valuable: proof.
Because people cannot predict future problems, they preserve evidence instead. A broken product, an unexpected dispute, or a forgotten date suddenly becomes manageable if proof survives.
Most receipts are never used.
That is precisely why they feel reassuring.
Their value comes not from solving problems.
It comes from making problems feel survivable before they exist.
