There are two things that come to mind:
1. The influx of talent, like Bryan, Punk, Cole, all had the big money contracts, while he, who is unequivocally one of the foundations of the company, had a less lucrative contract.
2. He lost the big matches. Despite being one of the most heavily featured acts in the company, Max usually on the bigger stage. He lost to Punk, and was on his way to being squashed by Wardlow.
If one sees it that way, it becomes clear that despite him being clearly seen as a valuable piece, he felt he was slighted.
Shame he might have fucked over one of the longest running storylines and one of the hottest rising acts.