It is the nature of the local derby that one side has often trespassed or transgressed on the other; so many different strands envelop Saturday's international.
Facing each other are two former Celtic managers who have their own personal pride to play for; the home team will supply two players who could just as easily have played for the visitors.
One of them, Aiden McGeady, suffered intense personal abuse in the reverse fixture in Glasgow for precisely this reason and his professional performance suffered alarmingly.
All the while, Shaun Maloney, a former club colleague in the very same Parkhead stadium, profited by striking the beautiful winner of an ugly contest; it was not the first time the scorer had trumped McGeady.
The Irish winger famously had a tumultuous row during Gordon Strachan's time as manager. Maloney, in his second spell at Celtic, ultimately benefited from McGeady's expulsion from the team; the warring duo would soon leave, manager first.
Tom Boyd, Scotland's fifth most-capped player and a Celtic club legend, identifies McGeady's alarming subsidence in his return to Parkhead as a key factor in the Irish defeat.
"He was a wee bit subdued in Glasgow," agrees Boyd. "He was getting booed every time he touched the ball. He'd been away from that for a while and he missed all those chants. But back here he will be getting the crowd behind him.
"We all know what Aiden's got - an abundance of skill and ability. He is an entertainer and fans love to see that. He has adapted his game under Martin (O'Neill ) in terms of the way he plays. He has developed into an all-round and complete player. He is certainly someone who could be a major influence in the outcome of the game.
"Consistency is always a question mark over really entertaining players and wingers. It's very difficult for these types of players to go and do it consistently, especially when you are up against decent defenders who do watch videos and who do watch what you are doing.
"To be fair to Aiden he has got a bunch of tricks in his locker. Normally you can watch a winger and say he can only go one way, but Aiden has five or six tricks.
"That's a blight on most entertaining wingers, being able to do it week in week out. It's consistency in their performance. If they beat a man, there's a big cheer. If they pass back, there's a groan.
"Maybe tracking back has taken a little bit out of it as you don't have the same amount of energy to take players on as often."
Which leads to the debate about style versus substance; Scotland stuttered but delivered on both fronts in the reverse fixture; Ireland seem hesitant to deploy any sense of style and hence are lacking in substance.
Boyd knows O'Neill's management approach better than Strachan's - the pair dovetailed to win a first domestic treble since the days of Jock Stein, as well as reaching a UEFA Cup final.
"The game has changed now and more teams are trying to play and, certainly under Gordon, it's more about the attractiveness of playing. Yes, he still wants to get the solidity but there seems to be a wee bit more openness.
"With the players that Gordon has got at his disposal and the way he has utilised them, he is certainly playing with more flair in the team and it is more pleasing on the eyes.
"Gordon's approach with the players seems to be different from when he was at Celtic. Maybe it's the players he has got at his disposal. And I don't think Martin has really changed his style right through his campaign."
Or his low-key approach until, before the game, he comes alive.
"At times he wasn't at training and Steve Walford would do most of it. But there was certainly a change in nature before matches while maybe a bit more low key during training sessions.
"He could keep a controlled aggression. I did see him lose it after one game. There were a few expletives after that game, he lost it a little bit.
"But he apologised to us later. I think it affected him.
"They'll be putting on a nice public face for the cameras, the two ex-Celtic managers and all that but deep down, both want to win.
"Scotland will win 1-0 with a set-piece with ten minutes left. I think there will be a bit more quality in this one and undoubtedly there will be passion but Scotland by the odd goal for me."
Tom Boyd was speaking at the launch of Ford's exclusive '152' Summer Sales campaign. See Ford.ie