Game designer Avery Alder took to Twitter to explain how credit cards, using a much more sensible and accessible framing than the magical metaphor that we typically use, which is "money."
The thread starts here:
You take a handful of gold coins, because you really do need the money. As long as you pay this strange creature back before the next full moon, nothing bad will come of it. Now, obviously the fairy is trying to trick you. You know that! But you're confident you can outwit it.
You borrow what you need, and you return it to that magical forest place before the moon fills. All is well. Better than well! The fairy grows fond of you, leaving you larger and larger piles of gold to borrow. Other fairies begin to make offerings to you as you walk the woods.
One month, life is particularly cruel to you. You can't pay back the gold you borrowed. On the night of the full moon, the being appears. "Don't worry, my sweet. I am merciful. Just give me what you have today, and pay the rest by next moon." It strokes its gruesome necklace.
"I'm sorry," you say. "I'll earn the money. I'll pay back the debt!" "Don't worry at all, precious darling! All in due time. Things have a way of working themselves out." And then, before disappearing in a puff of smoke, whispered under its breath: "that's the first finger."
The fairy keeps leaving you bigger piles of gold. The temptation grows stronger. Eventually, you come to think of it as *your* gold. You borrow too much sometimes, and can't pay it back. "Two fingers," it whispers without sound. Then three. It keeps letting you take more money.
One day, you realize that regardless of whether you make good on your debts, you can't stop borrowing more gold. Not only because you've built your life around it, but also because if you ever stopped borrowing it would make the fairies very angry. Not just this one. All of them.
You look around you at the world. Your fellow villagers have all fallen under the sway of the fairies. Borrowed fairy gold runs your whole town. People only do business with others if they are known to be in the favour of the fairies. Every day, more hands with missing fingers.
The savvy villager knows just what to do: borrow small amounts of gold regularly, to attract the attention and good graces of the fairies, and always repay it in full before the next moon, knowing it is not their gold. Get charmed and keep their fingers. Few villagers are savvy.
Anyways, "sinister temptations from the fairy mafia, who will love you dearly if you play their game right" is the framework that helps me make my best credit decisions. Maybe it will be helpful to someone else out there too.
Makes more sense than, "You want a pieces of paper whose only value is derived by the collective belief of our society, so we're going to use an NSA-derived spying metric to determine your capitalist morality and help us decide how many non-physical inherently valueless pieces of paper we will temporarily lend you, which you will repay us with additional inherently valueless pieces of paper as punishment for not already having enough inherently valueless pieces of paper of your own." And when you break it down like that, you start to realize that faeryfolk are actually more real than currency.
If you like this, check out some of Alder's role-playing games — I haven't played them myself, but if they take a similar approach to her credit explainer, then they're probably pretty cool.