Jantelagen: the code where mentioning wealth is taboo

Although discussing your wealth feels perfectly appropriate in some parts of the world, why does it seem like nobody in Stockholm is proud of being rich?

A high income is a badge of success in many countries, but in Sweden a deep-rooted cultural code called 'Jantelagen' stops many from talking about it.'

“Over in the States, when you say that you're earning a lot of money, people are cheering for you and they say: ‘good for you, good work’. But over here in Sweden, if you say that you have a good salary... people think you're weird,” says Stina Dahlgren, a 28-year-old Swedish journalist who spent several years living in the US. “You don’t ask about salaries, you don't ask about money.”

What's behind this don't-ask-don't-tell pheonomeon that's ingrained in Swedish culture?