#2 Mick Foley

One of the most memorable retirement U-turns in WWE came when Mick Foley returned to compete in the main event of WrestleMania 2000 against Triple H, The Rock and The Big Show.
Foley, portraying his Cactus Jack character, lost against Triple H in a barbaric Hell In A Cell match at No Way Out in February 2000, with the stipulation stating that he would be forced to retire if he failed to win.
The fans gave Foley a standing ovation as he left the arena and the veteran was legitimately supposed to retire following the show.
Five weeks later, however, with Vince McMahon concerned that Chris Jericho wasn't a big enough star at that point to join HHH, The Rock and Big Show in the Fatal 4-Way 'Mania main event, Foley returned at McMahon's request for one final match.
"The Hardcore Legend" lasted 19 minutes in the 36-minute elimination match before taking a four-year break from in-ring competition.