For Montreal it's probably drafting Claude Giroux instead of David Fischer in 2006. Prime Giroux added to the Price, Subban, Pacioretty, Markov, Plekanec, Gallagher group gives that team the true #1C it was always missing but without losing anyone important to that core through the butterfly effect of Giroux likely putting Montreal higher in the standings. Giroux breaking into the league for Montreal in 08-09 like he did with the Flyers also potentially prevents the Gomez/McDonagh trade from happening and potentially means Bergevin is never hired.