#1 CM Punk
Speaking of John Cena, The Rock and CM Punk had a series of matches in 2013, but as everyone knows, the fallout of their WWE feud led to another WrestleMania rematch between Cena and The Rock.
Punk could have still been included to make it a Triple Threat Match at the Grandest Stage of Them All, and being left out from the main event of WrestleMania did sit well with the Straight Edge Superstar.
In a 2019 Q/A session at Starrcast III, Punk revealed that heading into the 2013 Royal Rumble match against The Rock, he was unhappy that his promos were being written by the same people who wrote material for The Rock. However, both sides did reach a satisfactory agreement later.
CM Punk has been very vocal about being unhappy that he had to lose the WWE Title to The People's Champion, but since then, both Superstars have made up and Punk even apologized to The Rock afterwards.