It's not that Sepp Blatter hasn't heard boos before.
In fact, he's heard them often enough from stadium crowds that today, for the first time ever, he will break with World Cup protocol and not make an official opening statement to the crowd today in order to avoid them.
But yesterday, for the first time ever, he heard them in a FIFA Congress. Not loud or concentrated - the majority of the room still loves him - but unmistakeable.
That may be why he apparently chickened out when, in giving his closing remarks, he didn't follow the script and ask the Congress to express their "consent" for him to run for another term. Everybody knew that UEFA planned to express their discontent, some of it would have gotten vocal, and he wasn't prepared to deal with it.
He did use the opportunity to announce to everyone that instead of the $550,000 they were all handed four years ago, this time around he's giving them $750,000, that GOAL grants will be increased from $400k to $600k and that the confederations will all be awarded a cool $7,000,000 as a result of his largesse.
Then, the money he gives them being his main - indeed only - claim to their support, he shamelessly went so far as to tell them "My mission is not finished, comrades".
But at the big moment, when everyone was waiting for the charade to play out, he folded his notes and walked away.
Afterwards, in the post-Congress presser, he was in a churlish mood, answering one question he didn't like from a British reporter in French, and later went off on a rant about how rudely he had been treated at the UEFA Congress the previous day:
"Something like this, lacking respect like I saw and heard in the UEFA meeting, I have not had in my entire life"
The message from Europe is clear: Get used to it.
As Blatter moved among the various continental confederations this week, his main message, carefully repeated over and over, was what he referred to as "unity".
As in: "if we stay united they cannot defeat us. Together we are strong"
And everybody in the audience knew exactly who "they" are: those mean and nasty Europeans.
The point, as they all know very well, is that if the other five continents continue to support Sepp Blatter, they can bend the UEFA countries to their will. A cynic might call it extortion.
As we all surely know, this kind of thing is good politics: "Us Against Them" is a winner at the ballot box the world over, and Blatter is a both a terrific politician and an ace at math, and since UEFA only has around 25% of the votes, he can keep on winning elections this way as long as he can keep the money flowing.
And as long as the votes of Burundi, Montserrat and Outer Mongolia count for exactly as much as the votes of Spain, Germany and France, the math is in Sepp's favor. Not ever going to change.
But Europe may be getting ready to go John Galt. The Golden Goose may be getting ready to take a hike.
Picture in your mind a World Cup without Europeans or, more to the point, players who are under contract to teams in European leagues.
Down in Brazil this morning there are 622 players who ply their trade in European-based leagues, or roughly 75% of the total, and that number includes almost literally every big star in the world.
Yes there are around guys who play for teams in leagues in Japan (25) Iran (20) Honduras (14) Ecuador (12) and Chile (10). Please name two.
Time was that clubs were happy to have their players on national teams. It was a point of pride, and club officials would actively lobby federation coaches to get their guys onto rosters. It enhanced the prestige of the club to have "national team players" on the pitch and it was also an extra bit of cash for the players and a fun little vacation as well.
But that was before clubs were shelling out tens of millions of dollars for these guys, and before all the various games and competitions the teams have to enter - and the players have to endure - to justify the investment.
And it was also before FIFA started piling on mandatory international dates when clubs have no choice but to hand over their players to people who had nothing to do with developing them or turning them into stars so they can pocket some money and then send the club back a tired, sore and oftentimes injured (or at least nicked up) player who has to sit for a while.
So the way it looks from UEFA is that they spend millions and millions finding, developing, acquiring, paying and promoting players so that Sepp Blatter can grab them up, make billions of dollars off of them and then use the money to buy the votes that keep him in office and keep the system going.
And they see that they will never have the votes to change it.
What they can do though is quit. Pick up their chips and go home and, ironically, it's Sepp Blatter himself who is making it possible.
By itself, UEFA pulling out of FIFA, aka "The World Football Community" wouldn't play very well with the sporting public. It would kill everybody's favorite event and make them look like greedy bastards who are more interested in profits than sport, and they'd get murdered in the media.
Unfortunately, FIFA is handing them all the justification they need on a silver platter, and you can summarize it in one word:
The blatant corruption, the bribery, the slaughter of desperate foreign workers, the lies, the greed the arrogance and the obvious bought-and-paid-for nature of the whole deal simply stinks to high heaven. Everybody knows it and the whole world is disgusted.
This is emboldening the UEFA feds to an extent that Blatter has yet to fully grasp. To him, a world without a World Cup is inconceivable. It's his private piggy bank, representing fully 98% of FIFA's operating funds and constituting the sole financial support for upwards of 100 national federations, many of whom don't even pretend to have national teams or, really, any legitimate use for $750,000 generated by people paying to watch European club players compete.
Would they really take the nuclear option and cut loose from FIFA?
Up until recently it was unthinkable, but the time may be coming when UEFA will decide that they have little choice. Clearly they're beginning to think about exactly that.
Yesterday in Sao Paolo Blatter speculated about how, one day, instead of a World Cup, FIFA will host an "Interplanetary Cup".
And there's no doubt at all who he thinks, and the majority of the 209 member federations assembled before him hope, will still be running things on that glorious day when the Group of Death consists of Burma, Chad, Montserrat and Saturn.