Swedish business magnate Ingvar Kamprad had been at the helm of IKEA, one of the world's largest furniture stores and most beloved brands, for more than 70 years when his death was announced Sunday.

With a net worth of $48.1 billion at its height, he was one of the world's richest self-made billionaires.

If you ask Malcolm Gladwell, whose books have been read by millions of people, Kamprad succeeded thanks to an often-unpopular personality trait: disagreeableness, and not caring if people thought he was crazy.

From humble beginnings selling holiday tchotchkes to his neighbors as a child, here's how Kamprad started a privately held $11.8 billion furniture revolution and became a billionaire.