But the former policeman has another side too, and his bad cop routine is likely to be reprised if he doesn't get the required improvement from the All Blacks against France in Christchurch on Saturday.
The 23-13 victory over the French at Eden Park was a typical first-up performance from the All Blacks. It was a bit rusty but the French played their part too.
Hansen said as much afterwards but added he wants more and has given his starting XV the chance to make amends, although Brodie Retallick's hamstring, which he hurt in training late yesterday afternoon, could change those plans.
Retallick is likely to be given until this morning to come right. If he fails to pull through, Jeremy Thrush will make his test debut alongside Luke Romano. Steven Luatua would come on to the bench.
The majority of the others will consider themselves on notice.
One of the best examples of Hansen's ruthlessness was his treatment of Julian Savea last year. The then 21-year-old made his test debut against Ireland in the first test at Eden Park, scored a hat-trick and hardly put a foot wrong. A week later, in the cold of a midwinter's night in Christchurch which forced supporters to scrape ice off their car windscreens afterwards, he struggled a bit.
He wasn't as sure under the high ball as the Irish switched to a more pragmatic game plan and almost notched their first victory over the All Blacks as a result. It wasn't a convincing performance but the play didn't go his way and, besides, the conditions weren't conducive to his running game.
The consequence? He was dropped for the third test in Hamilton, with Hosea Gear getting a chance which he took well, claiming the No11 jersey for the next two Rugby Championship tests against Australia.
Who could be in line for the same treatment a year later?
Once again Israel Dagg is in the spotlight. Yesterday, Hansen defended Dagg's performance against the French in Auckland, and he was right to because the 25-year-old didn't have a bad game although the spark of the last few years is missing.
"I think Izzy is playing as well as last year minus those magic touches and it doesn't matter who you are, you can't be magic all the time. What we want from Israel is his core job done well and he's done that," Hansen said, adding that Dagg was one of the best fullbacks in the world at taking the high ball.
"The magic bits will come when the moment for him to be able to do that is available and the French didn't give him any. If you do your research you would say 'right, when he catches it we need to knock him over' and that's what they did."
The problem for Dagg is that Ben Smith isn't bad at taking the high ball either and the in-form Highlander must surely go close to claiming the No15 jersey next week even if Dagg performs his core roles on Saturday. With Smith and Rene Ranger in such compelling form it's time for a bit more than that.
While the All Blacks coach acknowledged Ranger was likely to take up his contract with Montpellier this year - reports have suggested it will cost him 300,000 euros to break his deal with the French club - the Blues bruiser, currently a bench player, will remain for the Rugby Championship and is adding to the pressure on Dagg.
"Rene knows what his role is and obviously he would like to start and at some stage he probably will," Hansen said. "But it's all about the team first and individuals second. At the moment for the team his role is to come off the bench and to do that really well."
As Hansen illustrated last year, those roles can quickly change.
