"Stupidity," Buffett said during an interview Monday on CNBC's "Squawk Box."
"I was impressed with Jeff early. I never expected he could pull off what he did ... on the scale that it happened," Buffett said Monday. "At the same time he's shaking up the whole retail world, he's also shaking up the IT world simultaneously."
"These are powerful, powerful ideas with big potential, and he's executed," Buffett said.
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