#1 Bret Hart
Bret "The Hitman" Hart became the face of WWE following Hulk Hogan's departure in the 90s. He had backstage differences with Shawn Michaels during his final years in WWE. At Survivor Series 1997, Vince McMahon double-crossed in one of the most talked-about moments in wrestling history.
Hart didn't want to drop the WWE title to Michaels at the event and McMahon agreed to the same. The boss had other plans in mind though and the match ended with referee Earl Hebner calling for the bell when Michaels applied the Sharpshooter on Hart.
For the next several years, Bret Hart slammed Vince McMahon on various occasions. The two parties seemingly resolved their differences in the mid-2000s and Hart was inducted into the WWE Hall of Fame in 2006. The relationship between Vince and Hart kept healing as years passed. They even had a match at WrestleMania 26 which saw Hart exacting revenge on McMahon for the events of Survivor Series 1997.
Hart and McMahon have been on good terms ever since and he has appeared for WWE on several occasions over the past 10 years.