#1 Former WWE star CM Punk
CM Punk and Triple H had an interesting rivalry when the self-proclaimed "Best in the World" was still contracted to the company, which broke kayfabe a number of times to show how deeply personal it had become.
Charlotte Flair to return and wrestle a CURRENT CHAMPION?
As part of CM Punk's infamous pipebomb back in 2011, he referred to Triple H as Vince McMahon's "doofus son-in-law" which wouldn't have gone down too well backstage.
Following Punk's departure from WWE back in 2014, the former World Champion went on to speak openly about his reasons for walking away and even spoke about the fact that he had never had "good vibes" from Triple H.
Punk also went on to note that Triple H called him two days before his wedding and he didn't answer but he did text him back and tell him that he was getting married in two days and would call him following his honeymoon. Punk then received a letter from the company on his wedding day informing him that he was fired.
It was later noted by PWInsider that one of the main reasons for Punk's departure was because he didn't want to wrestle Triple H at WrestleMania 30. This was something that reportedly offended The Game.
There's a feeling within WWE that while Triple H probably won't admit it publicly, he's probably offended that CM Punk didn't want to work with him at WrestleMania XXX. WWE officials, including Triple H himself, see being able to work with him as a big deal.
Triple H was later worked into a feud with Daniel Bryan and defeated by the former World Champion at WrestleMania 30 instead.