5: Sami Zayn, Post-Battleground, 2016
The most recent example on this list. After Sami Zayn defeated long-time arch nemesis Kevin Owens at Battleground in an incredible match, his momentum was through the roof. Finally moving on from the feud that had defined the first few months of his main roster career, it was on to bigger and better things for Zayn, and with the fans behind him after his hugely emotional victory, the sky was the limit on what Zayn could do heading into Summerslam.
Instead, WWE opted to have him drop matches to main eventers. No feud, no title to chase, Zayn was left stranded in the midcard. Not even having a match on the card for Summerslam until the last minute (where he was put in a meaningless pre-show tag match), it was a cruel misuse of the underdog from the underground who could have been elevated to upper midcard or even top face on Raw.