He enjoyed his time on the field but being separated from his family while in Japan, he had realised that there was more to having happiness than playing rugby.
"I was using rugby as my only tool of happiness. I think that sort of got me into a tough spot mentally," he said.
"Being able to take myself out of that and be happy outside of the game of rugby, and not need the game to make me happy, has made me a better trainer, a better player, a better teammate to my team.
"I think what I also came back with my mindset was what I owed to rugby for the support it gave me while I was away from my family.
"It was my constant. It was something that I knew that I had, every day," he said.
It had changed the respect he had for the game from wanting to be the best he could be for his teammates to respecting the game more for what it has given him.
That feeling of isolation in Japan and the lessons learned was something he wanted to help his All Blacks teammates with during their isolation in their tour so long away from home.
"The last thing I want is for some of those players to go through some of those darker moments that I went through," he said.
His appreciation of what rugby had given him was also a factor in his decision to stick with rugby after his touted switch to rugby league.
"Coming back and playing club rugby [with Norths in Wellington] with some of my best mates and my nephew was really cool, and to be able to give back to my club at this point in my career, I was really grateful for that," he said.
His decision to turn out again for the Hurricanes was confirmed when returning home after completing his isolation.
"Being back in the facilities, around the team and the environment. That cemented the decision for me and let me know I'd made the right decision.
"Being able to come home and give back to my club, stay with the Hurricanes, stay around Wellington, be with my family and pursue the black jersey, it definitely cemented that," he said.
While Aaron Smith was absent on paternal duty, the desire and competition were the same as when he was with the team. All halfback contenders wanted to be the best players they could be: that was part of professional rugby, so nothing changed, and all the halfbacks shared the same mindset.
Coming on as a replacement in the 38-21 win over Australia in Perth on Sunday, Perenara demonstrated his class and experience when pulling off an intercept, beating players and then putting in a well-executed cross-kick. It found replacement wing George Bridge who waited for the bounce before grabbing the ball to score.
"I didn't know it would be Bridgey out there, but I knew someone would be. We pride ourselves on getting forward on line breaks so, when someone does make a split, you often see a bunch of boys will get their head down to try and get up the field to be in support," he said.
Now the attention switches to a different challenge, playing Argentina, a side which enjoyed its first win over the All Blacks in Australia last year.
"We understand it's a bit of a beast this week," he said.
"They're a very big team, they play with a lot of speed and passion and they're very physical. That's not saying Australia aren't, they just implement it in different ways. They enjoy the one-on-one collision. They enjoy getting around the corner and coming straight at you. It's a part of our game we will need to adjust a little bit of our tactics to," he said.
"We know how good they can be when they get it going well."