Four reasons why Shake Shack is a 'sell' By: CNBC.com News February 02, 2015 at 10:34 AM EST Shake Shack is getting a lot of hype but Turney Duff, who knows a thing or two about eating and investing in burgers, says this stock is a "sell." Read More >> Related Stocks: Chipotle Mexican Grill Shake Shack Inc