Hawthorn defender Brian Lake chokes his opponent Drew Petrie. Photo: Channel Seven
After each game, as we're standing there in the showers, the talk is all about the contest. Usually we start with the lighter aspects of the game - players tripping over themselves, copping a "falcon", missing sitter shots at goal or getting in a good sledge. (There'll be plenty of time later for talk about "structure" and "process".)
The discussion then invariably gets around to the team we've just played and, more specifically, their players. There's open admiration for some but genuine disdain for one or two others.
And the reasons for that dislike can be many and varied: the player in question can be too selfish, too arrogant (when he isn't very good), too much of a sniper (when he isn't very brave), too lippy (when he's only been playing in the AFL for five minutes), too timid or too keen to go to ground in order to win a free kick - a ''stager''.
Sometimes, the source of the angst has its roots in a clash that happened years ago and has been allowed to fester ever since.
It might simply be significant egos pitted against each other, and one is considered to have overstepped the mark. A snide comment here or there, a quick hit to the ribs that's not appreciated. Unwarranted arrogance, excessive diving for free kicks ... all these things can cause ill will.
I started to ponder this question after watching the Brian Lake-Drew Petrie incident on Friday night. What could have prompted such a fierce reaction from Lake?
I don't know of any rift between Petrie and Lake, and suspect there isn't one. (I've never met Drew besides crossing paths on the field but from all reports he's a ripper bloke.)
But given how heated their clash was, you might be forgiven for thinking that there was a deep-seated, generational family feud between the two. Some players have long memories about on-field slights and will bide their time to exact revenge.
We saw an example of that in the Adelaide-GWS game at the weekend. Callan Ward cannoned into the Crows' Richard Douglas in an attempt to stop him from marking, making contact with his head in the process. Ward is a brutal competitor who is balanced and controlled at all times, but on this occasion looked uncharacteristically clumsy.
Could that have had anything to do with an incident last April when Douglas cleaned up Ward with a heavy bump off the ball and was suspended for two matches?
Did Ward ever so slightly lose his focus on the ball when he realised it was Douglas who was in front of him?
The answer is yes. I would say so! Ryan Crowley and Brent Harvey clearly aren't the best of mates either. Crowley stretches the rules to get the job done in shutting down the Roos' champ; Harvey has to deal with what he would term "unfair" tactics.
Crowley unsettles Harvey with "mental warfare", saying anything that may take his mind off the game. Harvey turns to the umpire at every chance to complain about his treatment, looking for a free kick.
A few matches like that and you can see how quickly genuine hatred can develop between two players. I'm all for pushing the boundaries, provided it is all left on field.
Jason Akermanis was one of the last players to openly air his dirty laundry. He was happy to speak about what was happening behind closed doors at the Bulldogs as he felt hard done by. It did wonders for his profile at the time, but largely put all his teammates off side. Not everyone will be best mates on a team, let alone with players from the opposition.
But such animosity does not need to be made public. Which is why former England cricket captain Andrew Strauss was forced to make a public apology to Kevin Pietersen last week after a very personal criticism of his one-time teammate was inadvertently broadcast when Strauss thought his microphone had been turned off.
The AFL is littered with such fraught relationships. It is such a competitive game, and we are all out there for the win only. The old adage of "what happens on the field stays on the field" remains the unwritten rule between players, but every now and then issues arise that transcend such a culture.
I've seen, for example, how personal grudges can become team grudges. I've had teammates reveal what some opponents have said on the field - and those comments will be used by the coach in a team meeting when next we play that particular side. The seed of hatred can be planted that easily.
Occasionally, women are the cause of angst between teammates or opponents. Some years ago, a player - let's call him Player A - had a relationship with a woman who, it transpired, was engaged to a player from another team. It's the make-up of the man that determines if he shares such stories on field ... and Player A chose to remind Player B of the relationship when they next crossed paths during a game.
This, understandably, did not go down well with Player B at all. And it's probably safe to assume his feelings of antagonism toward Player A remain strong to this day.
Gone are the days where such anger can be expressed out on the field via a whack behind the play or a good old-fashioned shirtfront. Our memories are just as good as our predecessors, but we are not afforded the luxury of evening the score in the way they were.
What occurred on Friday night between Lake and Petrie certainly was not within the rules of the game. Lake's actions were stupid, but they were not the acts of a sniper. It was not behind play, nor was it a cowardly king-hit from behind. It happened in the heat of a battle. And when players step over the white line and compete for the ball, rules - and clear thinking - can sometimes become blurred as that red mist descends.