Jericho came back to the WWE in 2007 after taking a break from wrestling, but he had a hard time getting a good feud going.
He stumbled around the first year, having bland feuds with JBL and Randy Orton. Jericho would still remain a fan favorite.
Everything would change in 2008 when Jericho would begin his heel turn. Jericho had placed himself in between a feuding Shawn Michaels and Batista.
Jericho was the special guest referee for their match at the Backlash Pay-Per-View in 2008, and would confront Michaels about faking an injury to win the match.
Eventually Jericho would have Michaels on the Highlight Reel, where he would call him out in front of everyone for faking the injury, and would also question how the fans still cheered for HBK even after he faked being hurt.
At first Jericho would tell HBK that even though he lost against Batista in a stretcher match, the people still loved him.
Jericho would eventually attack Michaels for lying to him about the injury, and send Michaels crashing into the Jeritron.
What makes this heel turn so fantastic is how Jericho, like Punk would do a year later in 2009, took time in building up his turn.
Then when he did turn, gone was the Y2J of the past, and instead Jericho had evolved into a completely different character.
He began coming down to the ring in a suit, with a smug look on his face. He turned into a egoistical villain and had fantastic promos which added to his character.
He would go so far as to punch Shawn Michaels' wife in the face.
Jericho showed the WWE Universe why he is one of the best in the business with his heel turn in 2008. He was able to completely rebuild his character, and become the top heel in the WWE.
A lot of heel turns can happen in an instant, but Jericho was able to build up his turn, and kept it going with fantastic promos. Jericho's heel turn was clearly one of the best in WWE history.