There wasn't just one. Mitchell Moses recalls at least a dozen blow-ups with the coach throughout the course of last year.
"It was week in, week out," a forthright Moses told NRL.com.
"I'd disagree on things, he'd disagree on things, and we'd let each other know about it."
It culminated in Moses virtually being shown the door. Time to move on.
That part of the story is well known.
But how did Moses convince Brad Arthur that he was worth taking one last punt on?
"I was always blaming everyone else," a forthright Moses said.
"That was my fault. For a long time I've been listening to all the outside noise saying 'it's not me, I'm not the problem, it's everyone else'. It took for me to wipe those people, who were filling my head with s***, out of my life to realise it is my fault. I am the problem.
"So I went up to Brad at the end of the season and said 'I'm sorry, I was selfish'. I had to look at myself in the mirror.
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"I'm glad me and Brad could clear that up and now our relationship is the best it's ever been. This whole year is because of him. He's put the boys in a position to play the footy we’re playing. It’s because of him."
Moses is a changed man, both on and off the field.
In the space of 12 months, he's gone from an unwanted wooden spooner to the driving force behind the Eels’ premiership push.
Moses opens up on his relationship with Arthur
The club couldn't have been more impressed with the way he handled his contract negotiations this year. It was done without fuss or fanfare, in stark contrast to the way he handled things at the Wests Tigers the last time he came off-contract.
"I had a few people in my life who used to tell me 'it's always their fault, their fault, their fault', no matter the problem," Moses said.
"They'd tell me it was never my fault, and I believed them.
"Since then, I’ve got those people out of my life and I just feel so much clearer in myself. I was always relying on these people, that they would always save me. I took it upon myself not to have those people in my life and I just feel so much better.
"I feel like I have taken a lot of ownership on myself. I've looked at my game - really looked at my game - and realised 'you know what, it's not anyone else's fault - it’s me'.
"I had to look it in that way, not relying on someone else in my life. My relationships with probably everyone else is so much better now. I had to learn the hard way, but I’m so glad it happened.”
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Moses has been maligned throughout his career, often criticised for an inability to play to his potential on a consistent basis.
He performed well when arrived at the Eels mid-way through 2017, helping the club reach its first finals series in eight years.
However, things went pear-shaped last year in a team with many strong voices, including the likes of Corey Norman and Jarryd Hayne.
"It's not as if Normy was the problem, he's gone on to play Origin this year," Moses said.
"It wasn't like Haynesy was the problem, either. Everyone had a hand in last year being such a terrible year. Everyone was rubbish.
"Everyone wanted to come back and prove a point. Not having those two players made everyone else stand up and take control a bit more. Everyone grew a leg."
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