Mark Cuban explains one of his top investing rules, courtesy of star venture capitalist Fred Wilson

Anytime someone walks into the pitch room on "Shark Tank" wearing a costume or making a spectacle, you can expect investor Mark Cuban to say, "Are you kidding me?"

The show's producers may like when entrepreneurs put on a show, but it immediately sets off a trigger in Cuban's mind, he tells Grantland writer Zach Lowe in the latest episode of Lowe's podcast.

His reaction is based on a principle he heard from Union Square Ventures cofounder Fred Wilson: "The longer the backstory, the worse the deal."

"If someone starts a pitch with a sob story, no matter how horrific and how heartbreaking it is, if you want to help them because they need personal help, great - but if they start with a sob story, always walk away," Cuban says.

"If they start with pomp and circumstance and all kinds of misdirection ... have a second thought," he says. "That's why you see me roll my eyes when all that stuff comes out, because I want to get right to the business. I want to get to the things that help me make a decision one way or the other."

Cuban says fellow Sharks Lori Greiner and Robert Herjavec eat that stuff up - and he knows it makes for great television - but it just doesn't make for good business.

You can listen to the full podcast episode at Grantland, where Lowe and Cuban discuss Cuban's pro basketball team the Dallas Mavericks, the NBA, and investing.