By Justin Barrasso ‘Their psychology has to be great,’ the WWE icon says. Since its inception in 1988, SummerSlam has brought life to WWE in the summer. Ironically, Vince McMahon created the event partially in competition against Jim Crockett Promotions, which is making a short-lived return this weekend with the Ric Flair’s Last Match card. The Flair match will run on Sunday evening, traditionally when SummerSlam airs, but this year marks a move to Saturday. In addition to a rare (but increasingly common) Saturday showing, this is also the first time SummerSlam has run in July. The event has b…