#1 WWE legend Stone Cold Steve Austin
Stone Cold Steve Austin impacted the pro wrestling business like no one else. He was the face of WWE during The Attitude Era. He helped the company become a household name again in the 90s. Stone Cold retired from pwrestling in his prime at the age of 38 in 2003.
Austin's career was nearly over when Owen Hart botched a piledriver to Austin at SummerSlam 1997 that seriously injured his neck. Thankfully, it wasn't severe enough to end his career and he made a return after a few months.
After his return, Austin created some of his best matches but his neck started give him problems again. Because of this Austin, retired in 2003 after he sustained a loss against The Rock at WrestleMania 19 to avoid any subsequent injury.
Austin later returned to WWE but he limited himself to a non-wrestling role. The Texas Rattlesnake definitely had some fuel left in his tank and he could've continued wrestling but he made the right choice to retire and protect his health.