#3 Chris Jericho turns on Shawn Michaels
In April 2008, Chris Jericho began his transformation from Attitude Era Y2J to a completely new man for a new era (which was admirable). Jericho had insisted on being the special guest referee for the match between Michaels and Batista at the Backlash PPV. During that match, Shawn faked a knee injury which caused Jericho to restrain Batista, allowing HBK to hit him with a little Chin Music for the win.
Jericho accused Michaels of faking the injury but Shawn maintained his innocence and Jericho apologised believing Michaels was innocent. Eventually, Michaels finally admitted he faked his injury.
During an episode of the Highlight Reel, Jericho pointed out that the crowd still cheered Michaels even though he attacked Jericho, faked and lied about a knee injury to win a match (which was fair enough). Jericho had finally had enough and delivered a low blow to Michaels before sending him crashing into the JeriTron screen. The backstabbing by Jericho may have kicked off arguably the best feud in wrestling of the modern era.