I asked my bank for a small loan.

This joke is a masterclass in wordplay, taking a common request and driving it to its most literal and ridiculous conclusion. The humor comes from the bank completely ignoring the spirit of the request for a "small loan" and instead focusing on the absolute smallest amount of money possible. They achieve this by weaponizing the classic, friendly idiom "a penny for your thoughts," turning a gentle invitation to share one's feelings into a stingy and unhelpful financial offer.

The punchline creates a perfect moment of ironic absurdity. We expect banks to deal in dollars and interest rates, but this one deals in sarcastic interpretations. The phrase "a penny for your thoughts" has been around since the 16th century as a figurative way to ask what someone is thinking. By making the offer literal, the bank not only denies the loan but does so in the most comically cheap way imaginable, leaving the poor customer with nothing but a single cent for their troubles.