Rand Richards Cooper at Commonweal:
In the Realm of Perfection dismisses this conventional wisdom and insists that we engage McEnroe on another plane altogether. The inquiry begins in our bemusement at the man-child. When McEnroe interrupts a match to vent, when he spits profane and acid mockery at line judges and referees, when he taunts fans or takes a swat at a photographer with his racquet—the crowd booing lustily—his matches approach the spectacle of professional wrestling, with its travesty of villainy. Why would a player aspire to that?
Faraut quotes a sports psychologist noting that such tantrums are counterproductive for most players. For them, anger of the kind McEnroe displays—tear-your-hair-out anger; threaten-bystanders anger—saps concentration and compromises performance. But not McEnroe. He wasn’t risking his game (nor, as many suspected, was he out to disarm his opponent); he was stoking his game by feeding on bad feelings.
more here.