#2: Ended too soon: Daniel Bryan
Daniel Bryan's retirement from wrestling remains one of the saddest moments in WWE.
A huge star, former world champion and massively popular with the fans, Daniel Bryan was forced to retire by WWE in early 2016, as his body was too badly damaged and the company worried he'd be seriously injured (or worse) on their watch.
Though the Yes! Man did get a role as SmackDown Live general manager, this only reminded Bryan on what he was missing, as rumors began to circulate that he'd be leaving the company once his contract expired.
Fortunately, this story has a happy ending, as Bryan was able to return to the ring in early 2018, and has spent the past year as one of the top faces, and later heels in all of WWE.