A Player will love a coach as long as he is picked and a coach will love a player as long as he delivers.
It is a mutually beneficial relationship. It has to be.
At the end of the journey, as long as both parties do their jobs, there is respect.
That is why Jonathan Sexton felt as though there was a target on his head when The British & Irish Lions played the New South Wales Waratahs in 2013.
His former Leinster coach Michael Cheika was out to rattle his cage, just like every other coach, really.
"Cheiks knew me, obviously, from when I was a bit younger and we had a few runs-in together and a few blow-ups," he said.
"But no, he probably would have tried to rattle the out-half as all teams do, but we had a good laugh about it afterwards. It wasn't dirty or malicious or anything like that.
"He's a fiery guy and I like that in him. You know where you stand."
There was a time at Leinster when Sexton was just another young buck out to make a name for himself, sure of what he wanted, not whether he would get it.
It was 2005, Cheika was new in town.
"I remember playing a Leinster Under-20s game, playing well and coming off with about five minutes to go," he recalled.
Leinster coach Cheika had been watching from the old stand in Donnybrook.
"I was just sitting on the replacements bench and he came down and I'd never met him before," said Sexton.
"He just tapped me on the shoulder and said: 'Great game. I'll see you training with the senior team during the week'.
"That was when I was 19 so it gave me the first lift in my confidence in my career and going forwards towards professionalism after that."
If that was the starting point, there were many bumps along the road from kid to king with one Felipe Contepomi standing right in his way to Leinster's precious number ten jersey.
"I was obviously very eager to break into the Leinster team," he said.
"When you are hungry and you want to get into the team you can be a bit delusional at times.
"I have to admit, how I thought I could get in instead of Felipe or Gordon (D'Arcy) or Brian (O'Driscoll), looking back now, it was a bit silly.
"But, I suppose it is better to be like that when you are that age than just sit back and accept it."
Ten years on, Sexton has elbowed his way to the top of the game as a winning British & Irish Lions Test No 10 and the best out-half in Europe.
The coaches that have been the biggest factors in his rise have been his first Leinster boss and his current Ireland coach Joe Schmidt.
"They are the two coaches I have spent the most amount of time with in my career, so far, and are the two that have left the biggest impression on me definitely," reviewed Sexton.
"They are similar characters in some ways, they are both fiery in their own way.
"They both want the best from the team and they drive high standards. I have learned so much from them."
The cumulative effect has been a nomination for the 2014 IRB World Player of the Year with four men from the Southern hemisphere.
"It was a shock to me to get nominated because mike Brown won Player of the six Nations and Andrew Trimble won pretty much every award there was in Ireland.
"It is obviously a big honour to get the nomination, never mind winning it."