#2 Shawn Michaels and the casket
Shawn Michaels is easily considered to be one of the greatest wrestlers in the history of the business, but one of the thing that held Michaels back for most of his career was his problems with his recurring back injury.
This injury was caused by a botch in a match against The Undertaker in a casket match back at The Royal Rumble back in 1998 where he was sent out of the ring and should have jumped over the casket but actually bumped his back on the edge of the object. The botch caused Michaels to cause him to herniate two discs and crush one completely, this injury caused Michaels a number of issues throughout the next few years of his career and one of the main reasons for his retirement back in 2010.