Every great hero needs a great villain to battle, for without evil, there can not be good. Without Darth Vader, there is no Luke Skywalker. Without the Joker, there is no Batman. In any event, nothing can revitalize a character like a good heel turn.
The most effective recent major WWE heel turn took place when Seth Rollins turned against his brothers in the Shield. Recently, some online fans have advocated turning either Dean Ambrose or Roman Reigns heel to fill that top bad guy spot, shaking up the main event scene and giving us fresh matches.
With all this recent talk about heel turns and how they could potentially greatly improve the promotion, I thought it would be a good time to look back through history at some of the best and most effective heel turns we've ever seen in wrestling. If WWE are going to go all the way and turn a blue eye into a villain, they could do worse than look to these for inspiration.