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New and developing investors who listen only to stock experts are doing themselves a disservice, Cramer said Friday. Some of the best advice often comes from the people who know more about the underlying businesses.

Restaurateur Danny Meyer sure taught Cramer a thing or two. Meyer, who owns New York’s Union Square Café and Gramercy Tavern, among others, said that companies who emphasize the customer would outperform during a downturn. Clients develop such a loyalty that they continue to eat, shop and invest with these firms even when the money’s tight.

Cramer at first doubted Meyer’s suggestion. But at look at stocks like Whole Foods , Chipotle , American Express , Apple and Goldman Sachs —all Meyer-blessed—versus the S&P 500 when the depression was at its worst showed higher share prices among those where the customer was king.

“Just when you thought everyone was trading down to Walmart or Taco Bell,” Cramer said, “Danny knew better.”

The bottom line: Listen to everyone, especially to people who know more about consumer behavior that’s different from your own.

“Otherwise you will miss out,” Cramer said, “on what look to be some totally impenetrable gains.”

When this story published, Cramer's charitable trust owned Apple.

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