Somebody should sit Cristiano Ronaldo down and explain why some of his own fans don't like him.
Everyone else knows. They whistled and booed because they think he's a selfish, preening, pumped up fool of a man who has an extraordinary gift but insists on trying to make everyone dislike him despite it.
It has nothing whatsoever to do with football. He's a genius and there's no sensible argument against that.
No, this is about his attitude. Put simply, he's Billy Big Boots and people don't like that.
There's a thin line between arrogance and confidence but not with Ronaldo. There's no line at all.
Every bicep bulging, six pack exposing underwear shot he appears in tells the world one thing: "I'm bigger, better, beefier and more beautiful than anyone else alive."
Every team photo he takes on tippy toes to make sure he's taller than everyone else falsely proclaims his physical advantage over his team mates.
And every time he looks for adulation after he scores a tap-in and ignores the player who beat six defenders to pass him the ball, he tells us: "It's all about me, nobody else."
A confident man wouldn't need to do that. An arrogant man would.
Football fans will forgive a great deal if a player delivers which puts the Real Madrid catcalls into context.
Even after all he has done for the club, they find reason to fault him and that can only be about his personality.
The whistling on Tuesday evening began long before he scored his 41st hat-trick for the club and at a time when Real were struggling. That's the crux of it.
No player is immune to the demands of the paying customers and if you hold yourself up as God's Gift and waste no opportunity to underline it, fans will become impatient when there is no end product.
This is just a natural response to a show off. It's fine when he's scoring but not so good when he's not.
Ronaldo never seems to have acquired the maturity that comes with recognising he has a wonderful skill and being grateful for it.
He wipes everyone's nose in his wonderfulness and in an age of no consequences, he believes that his goals mean he has licence to be the obnoxious, 32-year-old teenager he has become.
He has created a fantasy world in which his poor behaviour is irrelevant and everyone should bow down before his great talent and worship, no matter what he does.
Remember how he tried to turn the Bernabeu against Gareth Bale when he first arrived?
Like anyone with a "me, me, me" complex, he felt threatened and did his best to turn Bale into the crowd's favourite punch bag.
Ronaldo likes mirrors but he only sees one thing when he looks in them.
If he wants the real reason why he's not loved by some of his own fans and derided by neutrals, he should take his hands off the hair gel for a moment and take a long, hard look at himself.