There is a great Jewish joke about markets: Shlomo was returning from Antwerp, when he met Moishe: "Look at this bag of diamonds I've bought there! only 1000 florins, it's easily worth double that!" "Wow, that's a hell of a bargain, how much do you want for it? 2000?" "deal!".

Shlomo went home. He told his wife Sarah about his daily business. "So Moishe bought this bag for double the price without bargaining? He must know it's worth much more than that, you moron! Buy it back tomorrow!"

The next day, Shlomo met Moishe : "listen, I'll take back the bag of diamonds. 3000 florins?" "deal!"

That night, Moishe told the story to his wife Debrah. "Imbecile! can't you see you've been gamed? You're now 1000 florins poorer than yesterday, and what do you have?"

The next day, Moishe met Shlomo: "listen, I've think about it, I want to buy back the diamonds. 4000?" "deal!"

So this little back and forth game goes on for a week, when someday, Shlomo said to Moishe: "Listen, I'd like to buy the diamonds back after all..." "Too late, I've sold the bag yesterday to a merchant from Hamburg!"

"What? You've sold a stranger a bag of diamonds that was making us 1000 florins A DAY?"