#2 Brock Lesnar
Brock Lesnar quickly became the biggest Superstar in the company during his first stint with WWE in 2002-04. By the time 2004 came around, the pressure of WWE's hectic schedule had started affecting Lesnar, physically and mentally. He left the company on bad terms immediately after WrestleMania 20 to pursue a career in the NFL.
Things took a bad turn soon as a motorcycle accident resulted in Lesnar's NFL dreams getting crushed. He decided to contact WWE for a return but Vince McMahon wasn't happy with Lesnar's exit and made it clear that he didn't want to do business with him.
Thankfully for Lesnar, he made a recovery and went on to become one of the biggest stars in UFC history. His mainstream fame led to a WWE return in 2012, as Vince McMahon decided to forget their previous issues and signed him to a lucrative contract.
Lesnar has been with WWE ever since and has established himself as possibly the most dangerous entity in WWE history. His accomplishments include breaking The Undertaker's legendary WrestleMania streak and squashing John Cena at SummerSlam 2014.