With 43 Kiwis 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.
"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 Cowboys lock Jason Taumalolo - as well as the likes of David Fusitu'a, Manu Ma'u and Sio Siua Taukeiaho - from New Zealand 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 the near-certain evasion of Australia until the Cup final.
Mannering, who joins Joseph Tapine in the second row after missing last week's 74-6 thrashing of Scotland, admitted Tonga would provide a genuine test.
Their forward pack - including Taumalolo - was the envy of the rugby league world, and would be gunning for a unique feat in international rugby league.
No tier-two nation has ever defeated a tier-one nation.
"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."