#4 Brock Lesnar aligns with Mr McMahon
After an explosive debut for Brock Lesnar in 2002, 2003 was set to be the year in which 'the Next Big Thing' would firmly cement his place at the top of the wrestling mountain. The year started off perfectly with the Beast winning the 2003 Royal Rumble match. He then went on to main event Wrestlemania 19 and had even gone through a face turn following the events that transpired at the previous year's Survivor Series.
Despite being positioned as the top guy of the company in 03, Lesnar generally works better as a heel due to his size and aggression, and this was true even back then. Fans simply believe him more when he is bullying smaller guys or making a mockery of his fellow main event competitors by annihilating them with ease.
That's why, on an episode of Smackdown in August 2003, Lesnar swerved the WWE Universe and turned heel once again, this time aligning himself with the evil Mr McMahon.
The two were initially set to face each other in a steel cage match with Lesnar's Wrestlemania 19 opponent Kurt Angle as the special guest referee. After Angle refused to allow Vince to win the match with underhand tactics, Lesnar attacked the Olympian and celebrated with Vince as a result.
Given the fact that the Beast was gone from the company less than a year later, it's difficult to say whether he and Vince would have had many storylines together, but given the boss's preference for including himself in storylines that involve top performers, it does seem quite likely.
Alas, all we have of such a story angle is this shocking incident from 2003 which unfortunately didn't lead to anything significant.