With 43 New Zealand Test caps to his name, Simon Mannering has witnessed the highest of highs and lowest of lows in the black jumper.
And the stalwart back-rower believes a common thread runs through the side's greatest blunders since his 2006 debut - emotional over-investment.
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"I think that's where Kiwis teams in the past have got in trouble, when their emotions got involved, allegiances split and what-not," Mannering said.
"That's probably where we've fallen into the trap."
The defection of star North Queensland lock Jason Taumalolo - as well as David Fusitu'a, Manu Ma'u and Sio Siua Taukeiaho - to Tonga has overshadowed much of the Kiwis' Rugby League World Cup tilt, despite first-up wins over Samoa and Scotland.
In response, coach David Kidwell has attempted to keep his troops as emotionally detached as possible, focused on their own self-improvement.
And with the rampaging Taumalolo set to face them head on in Saturday's Pool B decider in Hamilton, they haven't veered too far from the script.
Mannering said he and his teammates had no intention to unleash hell on their ex-teammate and wouldn't use his presence as a motivational tool.
They'd simply look for a composed, disciplined performance.
"All that, players choosing teams ahead of others, that's all in the past and we've all moved on as a group. We've got a job to do for our country," Mannering said.
"The opposition, you definitely look at them a little bit in the sense of what they're doing in the tournament. But, we're all familiar with their personnel and what they do in a game, so we just try and focus on ourselves, build as a group."
The Test shapes as a crucial one for both camps, with victory securing top spot in the pool and almost certainly evading Australia until the Cup final.
Mannering, joining Joseph Tapine in the second row after missing last week's 74-6 thrashing of Scotland, admitted Tonga would provide a genuine test.
No tier-two nation has defeated a tier-one country.
"This is going to be our toughest challenge yet, no disrespect to previous opposition - it's going to be good," the 31-year-old Mannering said.
"A good challenge for our group, to know where we're at.
"It's probably harder for people outside the game to understand, but it is just a game. It's not sworn enemies or whatever; you just get out there and play."