'Shark Tank' investor Robert Herjavec reveals how deals are affected by what happens behind the scenes

Day 2

"Day two is inevitably the best," Herjavec says. The Sharks aren't distracted by what's happening back at their office and they're not concerned about hamming it up. They're acutely focused on making good deals.

"Those twelve-hour studio sessions have become our reality, and nothing intrudes on our assessment of the pitches (and the people making them)," he writes.

Day 3

Day three presents the biggest challenge to entrepreneurs because it's the least enjoyable for the Sharks.

As the day progresses, Herjavec says, "it becomes difficult to keep our minds off whatever we hope or fear is happening back at the office. It also becomes trickier to overlook little annoyances that were easy to shrug off a day or two earlier, when they might have earned a smile or a joke tossed between us for a laugh."

The investors start to itch to get back to their companies, and they're more likely to think about how cold, hungry, and miserable they are in the studio, Herjavec says. The producers enjoy the third day, he argues, because the ways the Sharks either attack an entrepreneur giving a weak pitch or attack each other over a deal when they're in this mood makes for great television.

That's what happened in Season 6, for example, when Herjavec yelled at Greiner and John for giving a "handout" to an entrepreneur he determined they felt sorry for, before storming off the set, with similarly disgusted Cuban and O'Leary not far behind him.

"Three days don't represent just the maximum number of days we can stay away from our businesses; it's the maximum number of days we can do our jobs as Sharks and still remain functional," Herjavec writes. "Not to mention amiable and courteous with each other."