#1 John Cena - Booked himself to be "WWE's savior" at SummerSlam 2010

In what can now be described as one of the most infamous WWE booking decisions of the last decade, John Cena and his team defeated The Nexus at Summerslam 2010 in the main event.
But why was it so controversial? For one, The Nexus was still new and they were the hottest part of WWE television. The angle felt fresh and the faction led by Wade Barrett was making strides quickly.
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Being in a match that involves John Cena, Edge, Chris Jericho, and Bret Hart isn't bad at all. However, the consensus seemed to be that The Nexus should have defeated Team WWE. Had they done so, their momentum would have grown exponentially and Wade Barrett would have had a legitimate chance of becoming a main eventer in WWE.
Justin Gabriel, a former Nexus member, revealed that there was a back-and-forth between Chris Jericho and John Cena about the finish (H/T WrestlingInc) and expressed his regret for not standing up against the decision.
“We should have changed the finish, but being rookies we didn’t want to be pushy. We all knew we should have changed it. Everything from that point went downhill. It should have ran for at least a year and put more of an emphasis on some of the characters," said Gabriel.
John Cena denied being the one responsible for the decision, but it seems to be widely acknowledged that he booked himself and Team WWE to win. Since he was already five years into his main event at this point, he should have put The Nexus over and helped establish Wade Barrett as WWE's next big star.