You shouldn't pretend to be someone you're not.
Jerry finds a wallet on a desk at the library with a credit card inside.
Jerry wants to react to the wallet.
Jerry returns the wallet to the library front desk.
Jerry takes the wallet back home and make purchases online using the credit card as if he was the cardholder.
The wallet owner thanks Jerry for returning his wallet.
The wallet owner feels frustrated and annoyed by Jerry's fraudulent action.