The chemistry of the parish is not always the chemistry of the county and that of the county is not always of the country.
Declan Kidney is the most successful coach of any generation for what he has achieved for Munster and Ireland -- a two-time Heineken Cup hero and a Grand Slam icon.
Before all of that, the seed of his genius was sown as a teacher and much-feted coach at Pres Cork, and when Ireland captured the FIRA U19 World Championship in 1998.
This is not to suggest he is unimpeachable or irreplaceable. He has had his failures, most notably in his short stint at Leinster when his pop-psychology was not as well-digested in Dublin as it was in Cork.
He was appointed head coach at Newport Gwent Dragons in 2004 for three months before high-tailing it to Leinster, which was nothing more than a stop-off on the way back to Munster.
Kidney returned to his homeland to realise his dreams. At the time, it was thought he was best understood there. Dubliners wanted technical innovation, not high-end motivation.
Subsequently, he was the only obvious option to succeed Eddie O'Sullivan. It was a risky appointment but he knows his strengths, his weaknesses and his limitations.
In this Six Nations, the Ballincollig native, 51, has shown uncommon tolerance for simple, stupid transgressions made in the name of adrenaline. He has sent out the edict -- no more.
Ireland's main issue is intolerance for change, a refusal to move with the times. The laws, or at least the interpretation of pre-existing laws, at the breakdown have changed and old warriors have to change with them.
Ireland's biggest problem is that, for all the banter about strength in depth and building a squad, Kidney does not have the trust and belief in those that lie beneath the surface.
All things being equal, Kidney will choose Donncha O'Callaghan over Leo Cullen every time, David Wallace at openside every time, a fit Tomás O'Leary over any other scrum-half every time, Denis Leamy on the bench instead of Dominic Ryan, Rhys Ruddock, Kevin McLaughlin, Chris Henry or Willie Faloon every time.
This is why Ireland will go to this year's World Cup without the experience needed to mix and match as the competition progresses.
It is the way of 'Declan's World' to talk about every player that isn't selected instead of talking about the unchanging guard he always looks to in a time of need.
This is one of those times when those that have been trusted to continue must carry the fight to Wales at the Millennium Stadium.
They must repay the faith of a coach who chooses to smile at the outside world when he was screaming in the closeted dressing-room.
Kidney has stood up to deflect and refute most charges levelled at his players. He believes Ireland are not a house in turmoil, just a building process in need of light renovation.
It is time for the players to do their work.