Eto'o's anger can be a forceful thing. It has drawn widespread attention to the problem of racism in southern European stadiums.
All not well at Inter as Eto'o loses head
Normally, when Samuel Eto'o loses his cool, there is very little surreptitious about it.
Eto'o's brilliant career is a story told through a catalogue of goals, spectacular ones and important ones, and it will, when he eventually retires, be remembered for its glut of trophies.
There will be some unedifying footnotes, of course, but most of them will surround his occasional inability to master a competitive nature and direct it to fruitful ends.
So part of what made Eto'o's headbutt on Bostjan Cesar, the Chievo defender, on Sunday so shocking was not so much the way the gesture mimicked perhaps the most notorious loss of restraint in football history - Zinedine Zidane's similar assault on Marco Materazzi in the World Cup final of 2006 - but its slyness.
Eto'o, as is well known, has in his character a powerful streak of indignation. It was being expressed even when he was a teenager.
Having been scouted by Real Madrid and whisked off to Spain, he felt opportunities were not as quickly available as his talent deserved. Real's error in not recognising the lasting impact Eto'o would have on the world game, is something Eto'o would remind them of for many years.
He kept scoring goals against Real, for a start, for his next clubs Real Mallorca and Barcelona, and would frequently celebrate them with an ostentatious gesture towards the club who had mistakenly let him go.
Eto'o's anger can be a forceful thing. It has drawn widespread attention to the problem of racism in southern European stadiums, notably on the occasion when he threatened to leave an arena, mid-match, in Zaragoza during a chorus of simian grunts whenever he touched the ball.
On other occasions, his profound sense of what is correct and fair has led him into conflict with teammates. One of the productive alliances in club football of the last decade - that of Ronaldinho and Eto'o in attack for Barcelona - was breached beyond repair when Eto'o, losing his cool in front of radio and press microphones, challenged the work rate being offered to the club by the Brazilian. He also criticised his then head coach, Frank Rijkaard, at the same time.
Eto'o would leave Barca later than both men, after adding a further European Cup - his second of three so far - to his glittering resume. When he did leave Spain, it was to a curious farewell from Pep Guardiola, Rijkaard's successor.
According to Guardiola, there was something amiss with the "feeling" the coach had for the player: Eto'o's short fuse, his noisy righteousness, lurked somewhere in the vague definition of "feeling".
Yet for a man who plays so competitively, Eto'o has a remarkably clean record in terms of red cards. He spent six years at Barcelona without a sending-off.
His last red card came, ominously, during a pre-World Cup friendly for Cameroon. In South Africa, he captained a failing team, and his rash behaviour in a warm-up match against Portugal - he received two cautions - might have been taken as an early signal that all was not well with his national squad.
Similarly, the violent gesture he made towards Cesar. Inter Milan were losing to Chievo at the time, and despite Eto'o's late goal - his ninth in 13 Serie A outings this term - slumped to a second successive league defeat and to sixth place in the Serie A table.
He had earlier scuffled with the Chievo centre-half, and received a blow to the face from Cesar.
Gianluca Rocchi, the referee, did not see the resultant butt, made off the ball, and nor did his assistants. But television did and that evidence can and will be used in judging the length of Eto'o's ban. Inter will miss him.
If one player has soared in what has been a wretched season so far for Rafa Benitez, the Inter coach, it is Eto'o.
He has been the team's totem, their head boy … at least until he lost his head.