8. Mick Foley
WWE.comNow, Mick Foley's inclusion on this list isn't to say he should never have returned to the WWE - which almost defies the reasoning for placing him on it. But, there was a time shortly after Foley left that he made a completely unnecessary return, which ruined a lot of his credibility. By the time 2000 had rolled around, Foley and all his alter egos had taken an absolute beating in the ring. Numerous injuries were capped off by knee surgery in 1999, but Foley still remained as huge as ever. Don't forget, it was just prior to that when he teamed up with The Rock (love it or hate it, that pairing worked), so when he came back at SummerSlam of that year to win the WWE Championship, it was a big shot in the arm for the company. Bizarrely though, they had him drop it the next night on Raw to Triple H, but that did lead to perhaps Foley's most brutal and gruesome rivalry, against Triple H. It built up to the point where Triple H would challenge Foley to a Hell in a Cell match at No Way Out - but if Foley lost, he would have to retire. As we all know, that amazing spot where Foley fell through the cage after being backdropped by Triple H led to a loss for Foley, and what should have been the end of his in-ring career. He had gone out on a massive high, and almost went out in the way that every wrestler would want to. His legacy was cemented, and his credibility was well and truly intact. Yet fast forward a few weeks, and Foley's retirement was ridiculously reversed for just one night. When he came back for WrestleMania 2000, it destroyed a heck of a lot of the credibility Foley had built up by going out in the manner he did, and it was almost like he (and the WWE) couldn't let go. Foley was never going to win that match at WrestleMania, and it felt like a poor decision bringing him back. Sure, having him return a few months after retiring could have made sense, but this was poor booking all round.