OAKLAND, Calif.—LeBron James is stressed out. That’s the easiest way to understand how good the Golden State Warriors are. They stress out the greatest basketball player of his generation.

The Warriors once again have a 3-1 lead on the Cleveland Cavaliers in the NBA Finals with a shot to win the championship in Game 5 on Monday night. The Cavs avoided a sweep and spoiled Golden State’s bid for a perfect 16-0 postseason, but now they have to win three more games. That’s as stressful as the NBA gets. It’s enough for a weeklong...