CM Punk has never been one to mince words and as he prepares for his debut in UFC later this year, he had some parting words for his former company, the WWE.

Punk spoke with Sports Illustrated's Extra Mustard blog about competing in the WWE and what it was like behind the scenes.

"It's definitely a competition," Punk told the site. "Backstage is so shark-infested and political. It's almost comical. A lot of people are more interested in the backstage goings-on than what they see on television. A lot of ways it's more fascinating. It's a competition for sure."

Punk walked out on the WWE in January 2014 and then signed with UFC that December, but he said many things led to him deciding to leave for a new venture.

"I'd say there were a lot of little moments," Punk said. "I'd accomplished pretty much all I wanted. I was getting tired of being on the road, tired of getting beat up. Most of the big reasons had to do with my health. Like getting knee surgery and then being told, 'You need to be in the ring in three weeks.' I'm like, 'That's great. I can suck it up and be the tough guy. But wouldn't it be smarter to give me six weeks?' Stuff like that. Again, it's so cutthroat and political backstage. I always felt like I was fighting. I'd much rather just lock the cage door and really fight it out."

The former WWE Champion said he had more control over his storylines than most people, but that owner Vince McMahon had the final say in the company's decisions. Punk said the life of a wrestler took its toll on him.

"When I stopped wrestling I literally lay in bed for two weeks," he said. "In a lot of ways I'm still decompressing for leading that life. I definitely went through a transitional period, probably with some depression mixed in-waking up and not knowing what to do. Normally you're waking up to catch a plane, in a different zone. But yeah, physically, you take a beating."

Punk also delved into the transition from the safer environment of wrestling to the Octagon.

"In pro wrestling, it's fake," he said. "People always get offended by that word. 'No, we like to say it's pre-determined.' For whatever reason, people get angry at fake; pre-determined eases the blow? It's fake. At the end of the day it doesn't really mean anything. So after a while, it was, 'Let's just really fight and see what happens.' Now I get to."

He also touched on generating fans, but having no control over the selected outcome.

"Well, that's another thing in that phony world," he said. "What does it mean to be a good fake wrestler? That's an identity crisis that I think I struggled with. It doesn't matter if you're the best; someone else picks who they want in the top spot."

Lastly, the "Best in the World" went back to politics among Superstars.

"You wonder, did you really punch me in the face? You say it was an accident but I know you and I think you're a p----- and I've seen you do this to other people," he said. "Are you doing this to me? Did you kick me in the ribs as hard as you can? No, no I would never do that! In [MMA] I know the other guy is going to try and kick me in the ribs as hard as he can. No, not maliciously. But I've been in the [wrestling] ring with plenty of guys where I'm wondering, is he is trying hurt me? Is he mad because he is losing? I don't have to deal with that bulls--- anymore. It's a godsend."

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