3. Jeff Jarrett
It is largely believed that the mere existence of TNA can be credited to the mutual hostility between Jeff Jarrett and Vince McMahon. The moment McMahon purchased WCW; Double J was left without a major platform to wrestle on. Jarrett was not delusional to the fact that Vince would never be willing to do business with him again and therefore decided to create his own company. While TNA is yet to make the WWE truly sweat, it cannot be argued that it is currently McMahons biggest competitor. The most heated exchange shared between McMahon and Jarrett came in 1999, when Jarrett essentially blackmailed McMahon into paying him a large sum of money to perform. Somehow the company had allowed Jarrett to remain the WWE Intercontinental Champion up until the day his contract expired, at which point he would make the move to WCW. Did Vince serious not learn anything from Survivor Series 1997? McMahon wanted Jarrett to drop the belt to Chyna at the No Mercy PPV; only his contract was set to end the day before the event. At the time, WWE had finally leaped ahead of WCW in the ratings war, so the idea of Jarrett being able to take the Intercontinental title with him to McMahons biggest rival would have been a huge blow to the WWE. McMahon reluctantly agreed to pay Double J the money he requested and the pair have been unwilling to do business ever since.