9. What If Steve Austin Hadn't Broken His Neck? - 1997
There are few butterfly effect moments in WWE quite like Owen Hart picking up Steve Austin for that piledriver and not quite getting him set properly. A seemingly innocuous moment (although it'll have felt plenty 'nocuous' to Austin) that changed the company in ways still being felt today. SummerSlam, 1997, one piledriver, one broken neck, and the rest was history.
The injury forced him to relinquish his Intercontinental Championship and wrap up the feud with Hart but, given his emerging popularity, the then-WWF were determined to keep him around in some capacity. The solution was to start a feud with Vince McMahon himself, whereby he could be kayfabe fired and allowed the necessary recuperation time.
When he returned to in-ring action he renewed hostilities with Hart, but the seeds of his rivalry with Vince and his gimmick as the ultimate anti-authoritarian had been sewn. After moving onto a critically lauded feud with The Rock and, by 1998, a WrestleMania Main Event angle with Shawn Michaels, he'd managed to usher in the very Attitude Era that would sweep the Monday Night Wars and create the monolithic mega-corporation we watch today.
Without that broken neck, it's likely Austin and Vince would have never clashed in 1997, and Fox would have just paid billions for the rights to WCW Thunder.