Why is it so hard to like Cristiano Ronaldo?
When the sublimely talented Real Madrid footballer was jeered by Dinamo Zagreb fans this week, he offered his own theory.
"They whistle me because I am handsome, rich and a great player," he said, with the usual modesty. "It is envy. There is no other explanation for it."
Could he be right?
All top-flight footballers are rich, many are handsome, and a few are truly great players. But not many tick all three boxes. It may well be that such a triple whammy of good fortune is more than most fans can bear.
Everyone loves Lionel Messi, for example, who is staggeringly gifted and wealthy. Yet he also has a nose like a potato.
Likewise, many people still love the multimillionaire Wayne Rooney, who is so skilful that his drooling manager compared him to Pele this week. True, but one can also compare him to the movie ogre Shrek.
As for Ronaldo's two Brazilian namesakes, Ronaldo and Ronaldinho, their vast wealth and ability are clearly tempered by the fact they resemble the "before" and "after" photographs of a terrible wasting disease.
Cristiano Ronaldo's theory of perfection-hating fans is further bolstered by the evidence of some footballers exaggerating physical imperfections to increase their popularity. This is particularly true in the United Kingdom, where tall poppies are advised to duck.
Gary Lineker, for example, was always popular in England, but never more so than when he was mocking his own oversized ears.
Peter Crouch is forgiven most sins simply by drawing attention to his gawky appearance, via that robot dance.
And, to return to Rooney for a moment, his (unfinished) public rehabilitation from spoilt brat to national treasure began this summer, when he happily confessed to undergoing hair transplant surgery. In his most savvy PR move yet, Rooney even posted pictures of his new hairline on Twitter.
This was a postmodern Samson effect. It was not the new hair that made him popular, but his readiness to admit to being imperfect.
And there is the rub. Fans do not hate perfection in itself, but the shameless flaunting of it.
David Beckham ticks all three of Ronaldo's boxes. He is handsome, rich and a great footballer, yet does not inspire the loathing that Ronaldo does. This may be due in part to the latter's potency: Ronaldo is in his prime and Beckham is well past his.
However, it is also due to humility. Since his World Cup nadir in 1998, Beckham has carefully cultivated an image of humility. For all the preening and posing, we also know about his extra hours on the training pitch, his commitment to his family and his careful respect for others. Or how about Kaka, Ronaldo's teammate at Real Madrid? He is also handsome, wealthy and a former Fifa World Player of the Year. However, as a devoutly religious man, he dedicates every performance to God, rather than his own brilliance.
If Ronaldo wants the booing to cease - and something tells me he could not care less - he should remember that fans do not mind players being perfect, as long as they pretend that they are not.
