Steve Ballmer pressed the heels of his hands against his thighs and leaned forward. He was sitting in his customary spot at Staples Center, along the baseline in the arena’s north end. Most NBA owners sit at midcourt and dress like the corporate executives with billion-dollar fortunes that they are. Ballmer was wearing a plaid shirt and casual pants. “I can’t wear a sport coat to a basketball game,” he’d said a few minutes earlier.