Credit: ABC News

"Hiring a coach is literally the hardest thing to do in the NBA," Dallas Mavericks owner Mark Cuban told me. "I think the hardest thing in all of professional sports. You don't know how he's going to fit with the guys you have. So literally the second most important hire after the coach is the team psychologist."

After a humbling third straight playoff loss to Oklahoma City, fans have to wonder what kind of conversations Cuban is having with both coach and shrink. Barring some sort of miraculous comeback, the Dallas Mavericks will not repeat as NBA champions, and with Dirk Nowitzki as the sole returning star in 2013, the billionaire's team-building skills will be tested once again.

But if "Nightline's" day with Cuban is any indication, that is exactly the kind of challenge that gets his juices flowing.

Since he turned his boyhood stamp collection into a money-making scheme and asked to move out of the house at age 11, Cuban says he's been driven not by the rewards of business, but the tooth-and-claw competition of making high-risk deals.

Selling powdered milk door-to-door may not have been his finest hour, but he says it gave him some of the skills that eventually led to a $6 billion payday. Whether it was luck or delusion that convinced Yahoo to hand over that much stock for Cuban's Broadcast.com in 1999, he still had the foresight to diversify before the tech bubble burst. Some of his partners lost it all, while he sits atop a multibillion dollar sports and media empire.

Over lunch at his favorite burger joint this winter, the famously candid mogul bounced from topic to topic, dispensing opinions on politicians, business leaders and the state of the nation. When his lawyer dropped by the table to discuss buying the Los Angeles Dodgers, Cuban wrinkled his nose and shook his head at outgoing owner Frank McCourt's demands.

"He wants to keep the parking lots and lease them back at a ridiculous rate," he said. "And he's sued everybody he's ever gone into business with."

In a wide-ranging interview in his owner's suite, Cuban had no qualms wading into election-year politics and calls for "the 1 percent" to pay more in taxes. Unlike many of his fellow billionaires atop the Forbes list, he agrees. And the attached video clip explains why:

Watch " Nightline" anchor Bill Weir's full interview with Mark Cuban on "Nightline" TONIGHT at 11:35 p.m. ET/PT