When Andy Farrell sat in his seat in the west stand in Twickenham on a Sunday afternoon last February and saw himself on the big screen a lot more than usual because of the hole Ireland were in, it was easy to wonder if asked himself: "What the hell have I let myself in for?"
Ireland were being bullied on the pitch by an England team captained and moulded in the ferociously competitive personality of Farrell's son, Owen.
Farrell Snr questioned after the 24-12 defeat whether he had got Ireland's build-up right. Sure, there was the harmless entertainment of Bono serving supper to Johnny Sexton.
There was the uplifting sight of Paul O'Connell passing on advice to James Ryan. There was no mishap like the playing of a video which may have offended the sensitivities of some players in the squad before an England-Ireland game like what the FAI curiously find themselves looking into this week.
But the very thing that Farrell had spoken about, "true Irish grit" - the very attributes you would foresee a Farrell-coached team have as a given - passion and ferocity, were largely missing that day against England.
There is a different kind of exposure at play when an assistant coach becomes the head coach. When a new boss comes in, change is expected.
When the assistant coach becomes the new boss, changes are not made in a vacuum, they are compared to how it was in the previous set-up that he was part of. So when Andy Farrell says he wants players "to be themselves" it feeds the notion that maybe they weren't themselves under Joe Schmidt.
An assistant coach is insulated, to a degree, from criticism so their job, attitude and personality are less affected and thwarted by public pressure and stress which can affect the thinking of a head coach.
You don't need to read through the recent autobiographies of former players to get a sense of how well liked and respected Farrell was as defence coach with Ireland and the Lions because you also hear it from the current Ireland players who still feel comfortable enough to call Farrell 'Faz' during press conferences.
An assistant coach, like Farrell, can be a precious ally to players, someone to bounce concerns off, to confide in, and he also has that deep appreciation of a player's perspective because of his son. So, Farrell was probably seen as more holistic compared to the head coach Schmidt, a balance that brought tremendous success.
As well as his obvious expertise and the idea of 'continuity' at the time, Farrell's popularity would have helped him land the job of Ireland head coach. But how do the traits that helped him get the job survive when he gets exposed to a whole new level of stress and pressure as the boss?
Does he change then too? Does he have to have a different relationship with players because he's now the one who has to make the tough decisions like dropping a player?
And how do players react if they see their former assistant coach change under the pressure of being the head coach?
It's easy to see why a defence coach would appear to be a natural fit to become a head coach. We've seen Tony McGahan and Les Kiss make the jump to head coach roles in Irish rugby in the past.
A defence coach deals with the whole squad, as opposed to set-piece coaches. A defence coach needs the ability to communicate clearly and in a way players fully understand or else that can be brutally exposed during games.
A defence coach needs to have a passion for what they're talking about so players will play with that same passion in defending.
A defence coach needs to be innovative or at least quick to notice, copy and tweak new trends for their players.
A defence coach needs absolute buy-in and loyalty from players because of the motivation and enthusiasm required for a good defence.
And yet all of these characteristics still don't guarantee or protect a defence coach from appearing out of his depth when it comes to crossing over to the head coach job.
This mismatch doesn't just happen in rugby, of course. Look at trainer Cian O'Neill. O'Neill was part of the 2010 and 2014 All-Ireland-winning Tipperary hurling and Kerry football squads before he later took over as Kildare manager.
He had that famous 'Newbridge or Nowhere' qualifier win over Mayo two years ago but his four-season stint in charge of his home county didn't reach the heights he undoubtedly would have hoped for.
Now he's back to his specialist role as a trainer with the Cork footballers as they prepare for a Munster final tomorrow.
You only had to see how the Cork players listened and hung on his every word during Cork's shock win over Kerry a few weeks ago to appreciate how well respected O'Neill is within that set-up.
Ambition keeps the world moving, for sure, but it can also be someone's undoing because ambition can dilute the very thing that made you excel and stand out in the first place and can therefore turn you from a position of strength to a position of vulnerability.
Farrell doesn't have much distance - both geographically and figuratively - from his former number ones. There will always be comparisons made with his predecessor even if it fell apart in Schmidt's final year in charge.
Down the road from Farrell in south Dublin is another one of his former bosses. No coach in Irish rugby has really come close to matching the level of praise that was given to Schmidt but Stuart Lancaster has long been building an outstanding reputation with the job he's doing with the talent at Leinster.
And no matter how well they may personally get on, it must feel a little awkward and uncomfortable for Farrell at times if the former England head coach is sometimes spoken about as a future Ireland head coach. And then there's Farrell's former Saracens boss.
Today is the first time that Farrell will come up against a team that's already beaten him, and beaten him well at that, as a head coach.
There's no big expectation that Ireland need or should beat Eddie Jones's England at Twickenham today considering the inexperience of this new-look Irish team, but there is pressure that they're not bullied or exposed the way they were in the Six Nations in February.
What will be even more interesting is what Farrell has learned from that defeat. Because it was very rare that a Schmidt-coached Ireland team were beaten by the same team twice in a row. And thus the comparisons continue!
When Farrell took over as Ireland head coach he said he's taken bits from every coach he's worked with but also added "I want to be myself" and that "imitation's not a great thing, you know. That's more like acting".
When Johnny Sexton showed his annoyance at being substituted in Paris last month - which former Ireland head coach Eddie O'Sullivan believed "undermined" Farrell - the Ireland boss subsequently backed Sexton in public and Sexton apologised to him in private.
Farrell doesn't appear to have let his ego get in the way and fobbed the whole thing off as just a storm in a teacup. Would another head coach have been as forgiving - even in public?
There's an idea that assistant coaches have to change when they get the top job. Maybe that's where they can also go wrong.
If Farrell indeed stays true to himself and his nerve isn't affected by the pressure and stress that will inevitably come his way, then the very traits that made him a very successful number two could go a long way to helping him become the kind of number one he wants to be.