Any coach leaking passion will not cut it at the top level. That's part of the puzzle Steve Hansen had to answer when he was deciding about an extension to his All Black contract.
He loved his footy, there was no doubt about that. That would never evaporate but did he have the appetite for the rest of the job.
Hansen had to ask himself whether he was as enthusiastic every day about the time away from home, the planning and all the detail around the job; did he want to push himself and his squad to be even better for the 2019 Rugby World.
He has shown repeated shrewdness since taking over the top job in 2012 and an ability to listen, learn and interact with a wide range of other strong minds in the game.
Hansen took his time to consult various people and satisfy himself he was doing the job for all the right reasons before he gave a thumbs up to the New Zealand Rugby offer.
He was still as passionate as all hell.
Michael Cheika is too but if he is serious about helping rugby in Australia and round the globe, he needs to look at himself a bit more in the mirror.
At the moment he is coming across as a bad-tempered, foul-mouthed whinger whose coaching ideas, like the administration, are running on some very dodgy fuel. It is a constant splutter of complaint or excuse.
The All Blacks have been there too and it's a hellish cycle of descent to break. Resolutions are complicated and clear minds are a key.
Rancour, acrimony and resentment have to be diverted into powerful energy and mental strength.
Admiration for Hansen has not always been prevalent. His approval ratings were always higher with his players than those outside the club or provincial tent. Hansen was big on skills, detail and innovation and loved the us against them mentality he could add to the mix. He still does but has modified that stance.
Somewhere along the journey the lights widened. He would be a better coach and his teams would go up a cog too if he shared himself with the public. The messages were about embracing the world rather than railing against it.
Hansen took time, lessons and plenty of advice on how to work through the pressure and spotlight of being a national coach and after a bumpy beginning, has walked into a warmer relationship with the nation's rugby followers.
It's been a massive help that the All Blacks keep winning and in style but that is a product of his work. Away from the spotlight, Hansen can switch on his Mr Nasty buttons but he picks his time and place.
Cheika appears to have an automatic spray nozzle. He rails against the world.
He has a tougher path because of the shrinking talent pool in Australia linked with the over-ambitious expansion of teams in Super Rugby, limited numbers of coaches, competition from rival codes and uncertain commercial support.
The Wallaby coach has form for verbal vendettas and the sort of incandescent moaning which lit up the Wallaby coaches box and did not need a specialist lip-reader to decipher.
Every international coach knows cameras are trained on his work station and most are smart enough to work with that intrusion.
Cheika needs to turn the foam on himself. What has he done to deliver a Wallaby team to peak performance and how has he stacked up on the private and public graphs? He needs help on multiple levels. When he had a strong run with the Waratahs and was promoted to the Wallabies, much was made of Cheika's personal vision and drive to coach because his significant personal wealth meant he did not need the job.
He still has that financial treasure but the Wallaby stocks are going through the floor.