It had nothing to do with his side being thrashed by the Wallabies in Perth or even the recent accusations from Boks rival Rassie Erasmus that referees naturally favour New Zealand.
It was the suggestion that All Blacks skipper and No 8 Kieran Read isn't playing well, a narrative that took hold among some sections of the media despite Read's powerhouse defensive performances against the Wallabies over the preceding few weeks.
Hansen's feelings were made clear via a reporter's question to Read following the All Blacks' warm-up win over Tonga in Hamilton a couple of weeks ago.
Hansen, sitting alongside his captain, conspicuously rolled his eyes as Read was asked about his recent form, and, asked to explain his reaction, replied: "I'm just pretty disappointed with some of the questions you're asking.
"Most of them you could answer yourself. Ask us something that we can actually talk about that would be invigorating for the fans to read."
The specific reason for his annoyance was left unsaid, but it was without doubt centred on the implied criticism of Read.
There's no doubt Read's role has changed over the past few years from a wide-ranging link man to a more direct and central character at the breakdown – both with and without the ball. But that's hardly surprising given the evolution of the All Blacks' game plan, and the establishment of Ardie Savea in the loose forward trio alongside Sam Cane has probably cemented it further.
With Savea capable of footing it with midfielders and outside backs in terms of pace and finishing ability it follows that Read will play a different game.
Against the Wallabies in Perth he made 22 tackles as he and his side chased the game in Scott Barrett's absence due to a red card, and seven days later Read's defence was defined by a brutality perhaps not seen on a consistent basis since Jerome Kaino moved on four years ago. He seriously rattled some bones and the Wallabies were rattled mentally as a result.
Read hasn't suddenly turned into an "enforcer" type player like Kaino was but he nevertheless plays a massive role in leading the defensive effort and that is likely to be crucial against a giant Springboks pack in Yokohama as the All Blacks kick off their World Cup defence.
"It is probably the first time I've been the biggest loose forward starting, but it's across the board that we have to be physical against this South African team," Read said in Tokyo. "I pride myself on my defence and making sure I'm leading that as much as I can. But as I said, it's got to come across our whole team. We know when we're all on it tends to work out for us.
"It's going to be a massive game. The South Africans are going to be well and truly up for it so we can't wait for it.
"South Africa in the opening game of a World Cup is going to be one of the bigger games of your career so I'm really looking forward to that."
Marking Read, a 33-year-old 122-test veteran in his final weeks of his All Blacks career, will be Duane Vermeulen, a large and explosive No 8 about to win his 50th cap for the Boks.
"I thought I'd probably played 50 against him myself," Read said of his opposite. "It's surprising - I thought he'd played more. He's a top bloke and a very aggressive man and just loves to carry and tackle hard. I enjoy that challenge."