Lewis Hamilton and Nico Rosberg's collision during the 2014 Belgian Grand Prix provoked a huge reaction from fans and the media.
Mercedes reacted by fining Rosberg, and the German apologised to both the team and Hamilton. But both were relatively empty gestures and won't have placated Hamilton one little bit.
Their relationship now looks beyond repair.
The two men will spend the rest of the season locked in battle, not only for the title but for the hearts and minds of those within their Mercedes team.
Luck and physical ability will play a key part, but the mental state of a driver is perhaps more important than both.
Rosberg will most likely take heart from the aftermath of the Spa incident. Whether deliberate or not, it was clearly an avoidable accident and clearly the German's fault.
The secondary steering movement—seen here in a still image and here on Sky Sports' website (UK users only)—he made that brought him into contact with Hamilton's wheel was unusual to say the least and was always likely to cause a collision.
But he got away with it entirely. The FIA did not look into it, and Mercedes doled out nothing more than what the Daily Mail reported as a six-figure fine.
Whether at the high- or low-end of six figures, it won't have bothered multi-millionaire Rosberg at all. He may feel that he could do it again and suffer no consequences.
Having twice come out badly from what he saw as dirty tricks, Hamilton's mental state may be negatively affected. He feels that he has on two occasions been cheated by Rosberg, and received no justice on either occasion.
In the past he has displayed something of a "victim complex"—most notably at Monaco in 2011. If he feels the world, and perhaps even his own team is against him, it's unlikely to have a positive impact on his driving.
An alternative is that having these two incidents on his record may work against Rosberg. He could feel that he is skating on thin ice, and that any future transgression will be pounced on and harshly punished.
Hamilton may feel the same way, and therefore the "freer" of the two.
But it's more likely this factor will swing things in Rosberg's favour.
Rosberg's 29-point championship lead will also play a major role.
On the surface, there's no way to look at this other than as an advantage for Nico.
With 25 points available for a win, he knows he can fail to score in Italy—for any reason—and retain the championship lead regardless of what Hamilton does.
But such a large points lead brings with it the pressure of knowing the title is now his to lose. Rosberg has never been in this situation so late in the season before with a world title at stake—but did have a similarly large lead after the opening race of the season.
Hamilton closed that gap with four straight wins. That streak—and the knowledge it could easily happen again—surely plays on Rosberg's mind.
As will the fact that the lead only exists because Hamilton has lost so many points due to problems beyond his control.
Hamilton knows this, too. He has, over the course of the season, performed at a slightly higher level in the races (if not in qualifying). Were it not for multiple mechanical failures and the Spa puncture, he would not be 29 points in arrears.
In addition, per ESPN, he has said in the past that he would rather be the chaser than the chased, so being in his current position may prove advantageous.
Especially with double points at the final race.
On the other side of the coin, he also knows that he can't really afford any more errors, failures or inconvenient punctures. This will almost certainly remain in the back of his mind every time he goes out on the track.
There are positives and negatives for each driver here and each may feel he has the edge.
But perhaps the most important factor in the psychological battle will be how each driver feels toward those closest to him—the Mercedes team.
Rosberg recently signed a multi-year contract extension to remain with the German squad. Sky Sports reported the deal is thought to run until the end of 2017.
The team know he's going to be around a while, and Rosberg can feel secure in the knowledge that he has a top-level drive for at least three more seasons.
The same can't be said for Hamilton.
His current deal expires at the end of next year, but discussions over an extension have been meandering around for a while and gone precisely nowhere.
Officially the reason is that neither side wants discussions to take their attention away from the title fight, but could it be that one or both is getting cold feet?
Do Mercedes really want to commit to three more years of bitter rivalry between Hamilton and Rosberg—and does Hamilton really want it to carry on with a team-mate he can no longer trust?
It is, of course, possible that Rosberg could be shown the door despite having a contract, but that would be both expensive for Mercedes and terrible for public relations in Germany.
That isn't going to happen—advantage Nico here, too.
The only safe conclusion is that Rosberg will head into the Italian Grand Prix in a more relaxed, confident frame of mind. The championship lead and security that his contract provides will see to that.
And he certainly won't be losing any sleep over the wrist-slap fine from Mercedes.
Hamilton, considered the more emotional and erratic of the pair, is at a disadvantage. He feels wronged and cheated, and his frustration over the way the season is going is unlikely to work in his favour.
If he can come out on top at Monza, the pendulum will swing his way.
But for now, the edge lies with Rosberg.