Not the biggest rematch in terms of match quality (or popularity), The Rock and John Cena's bout at WrestleMania 29 was nonetheless one of the most monumental second clashes of all time. Their first bout a year earlier had drawn huge numbers - exactly the result the WWE were after - and a sequel was hastily arranged. Many speculated that another major reason was to allow Cena to "get his win back", having lost via Rock Bottom. The major downside of this was twofold: firstly, the initial match had been billed as "once in a lifetime", raising fears that a second encounter would cheapen the significance of both; secondly, it led to a year of incredibly predictable booking. The WWE's eagerness to make it a title match overshadowed every other storyline in progress. It resulted in CM Punk's amazing reign come to a depressing end at Royal Rumble 2013, before new champion Rock barely showed up over the next few months. Eventually WrestleMania came around, Cena won, and the wrestling world breathed a collective sigh of relief. Until they eventually decide to do a final decider, that is...