In Johnson's case he explained he had undergone considerable agonising about taking on the role of head coach because of the closeness of his relationship with Andy Robinson, who had appointed him as an assistant before being sacked from his job.
Asked if he is interested in taking on the head coach's job on a permanent basis after the stint he has agreed to, which will encompass the RBS 6 Nations Championship and Scotland's summer tour, Johnson said he will only judge that, in tandem with the Scottish Rugby Union board, after those campaigns are over.
"I didn't come here to do this job. I came to work with a guy that I really liked and I really respected," he said."I took it because I thought it was the right thing for the team. They needed to compete in a tournament and I was there to [help them] do that and so I agreed to do that. We will reassess that in June/July."
To that end the 50-year-old expressed relief at having coaxed Ryan, who works as an analyst for Sky's rugby coverage, out of coaching retirement, albeit briefly.
"Given the timing we had, I'm really pleased that we've actually got the person who was probably at the top of the list anyway," he said. "I was glad that Dean was available. We were in a great predicament when Andy left. I came in to do a job with Andy, who is a good friend of mine and great coach and his loss has been bigger for me than people realise. When I looked around I wanted someone who was mature, knew the game in the north, understood forward play and could command a room and was a good bloke. There's a few boxes ticked there and he said 'yes'."
Ryan, meanwhile, wasted no time in making it clear he has no interest in long-term involvement in coaching, before hinting at real disgust at how he was treated when parting company with Gloucester in 2009.
"There were a lot of things that frustrated me," the 46-year-old said. "Some of it was frustration with what happened at board level, some of it to do with how quick we were to dismantle something. Gloucester can be compared to Clermont-Auvergne who missed the title two or three times but kept the same structure and now look like they might be European champions. From the outside that speaks volumes.
"Why would I risk my children's schooling and my livelihood on people like that? I also managed to find a career doing something else, which I didn't think would happen. There are a lot of reasons.
"However, Scott turned up and asked if I fancied doing 12 weeks. Can I provide some stability? Think we could give someone a knockout blow? That lights a few fires that are probably always in me.
"Part of the attraction is giving people bloody noses. I like that. Where we are sets us up so that we can give people bloody noses. I'm not going to be around in two or three years, so it's not about evolving something; it's about 12 weeks. That's pretty good for me."
Those who remember his playing days could be forgiven for observing that Ryan is intent on sticking to what he has always done best. This is no mindless second-row thug, however, and Ryan, who admitted to knowing the Scottish players only from what he has seen on TV, knows he must get the mix right in terms of the messages he gives those heading into sporting battle, rather than merely offering opinions to a camera.
"The game's a fantastic game where you can make it really emotional and it works for you and, on another day, it needs to be really technical and you've got to get those things right," he observed. "I've got to balance what we're going to be working on and getting that emotional level right.
"I'm not going to just pretend there's a theory out there. I won't know until I see people in a squad session, I work with them and see how they respond to me.
"I'll give an honest message. I guarantee that it will be honest. That's part of the accountability of changing rooms. I'm not here to spin a story and create smoke and mirrors about something.
"I'm going to set [out] two or three things that we really want to improve on and work really hard trying to illustrate what they are and then we're going to be accountable for delivering them. That's the systems that we're going to put in place.
"Ten days is not a great amount of time to make progress so it's about making clear identifiable areas that you can make progress in. That's just about being honest.
"Okay, I might sit in a TV studio and dress things up slightly differently, but if there's one success I've had in moving to TV it's that I have stayed open and honest and that's not going to change when I go inside a dressing room.
"We need to define a game-plan, make sure our emotional levels are on par with the clarity of that game-plan and it's quite clear from looking at some of the games that there are some issues around contact, but it is too simplistic to just go 'Oh we'll go and tell them about that and it will all be solved'. It's about how we move, how we play."
Johnson, who is looking rather longer-term, noting that he will, in close calls, choose players with the future in mind, compared the squad with what he encountered when he first arrived in Northern Hemisphere rugby around a decade ago, while offering a message that others at Murrayfield might heed.
"There is the rugby skill set and the athletic ability," he said. "I have worked in countries where they are very fortunate in what they have at their disposal and some where they were less fortunate. This country is very similar to Wales in the early 2000s as they have the spine of a team that is athletically gifted, there's no doubt about that. If we get that part right and we build a team around that and work on what is important to us and not chase rainbows then we will get more good results than bad. We have to understand that's the kind of country we are."
Talk of winning World Cups would, then, seem to have been put on hold . . . for now at least.