What is it that is making Cristiano Ronaldo sad? So sad, that he won't celebrate his goals - the one thing that defines him?

Cristiano Ronaldo, Real Madrid's most gifted star, stunned the footballing world when he made public his existential crisis recently - no, it wasn't a shortage of hair gel or all the mirrors at his home shattering - when he declared after a Spanish Primera Liga game that he was sad despite putting in a match-winning performance, where he scored twice as thousands of fans chanted his name.

The Portuguese star's subsequent explanation in the post-match press conference puzzled journalists just like his strange fashion sense over the years has puzzled the most lenient of critics. "I am sad and the club knows it, that's why I didn't celebrate the goals, " he had said with a look made famous by the likes of football's frown club founders Dimitar Berbatov and Nicolas Anelka. "The people in the club know why. " The Madrid-based press naturally wondered if it was something they had done, but for the rest of the world, Sad Ronaldo, much like Fat Ronaldo years earlier, became social media's latest whipping boy.

Sadness may be an issue of concern that may even require a course of treatment, but not many people, even within the footballing world, were prepared to take Ronaldo seriously or even offer him any sympathy. Why would they? Rich, handsome and talented Ronaldo has got the best cars in the world, mansions and lucrative endorsement deals that deify him - even a Russian supermodel girlfriend, unperturbed by the odd wardrobe malfunction. If the 27-year-old is sad about kicking a ball about for a few hours a week, being paid an annual salary of 11 million euros and going home to the stunning Irina Shayk each day, then his misery is enviable. Especially so for the people in the country Ronaldo plays in, as Spain battles new levels of unemployment each week.

"If he's sad with the lifestyle that he has, then I want to be sad like him too, " said AC Milan CEO Adriano Galliani. "If Cristiano is sad, people should go into the streets and cry, " former Barcelona coach Carles Rexach remarked at his sarcastic best. The Catalan added: "Ronaldo can't ask for more from life. He's a top player, he has everything. He is physically fit, well-built, has money, success, one of the best players in the world. I don't know what else he wants, so for him to be sad is sacrilege. "

Ronaldo's attempt to explain his sacrilegious statement a few days after making it didn't really clear much up. "That I am feeling sad and have expressed this sadness has created a huge stir. I am accused of wanting more money, but one day it will be shown that this is not the case, " he tweeted prophetically. This came at a time rumours trickled in that Real had planned to offer their prized possession an anti-depressant in the shape of a bag that holds a handy 5 million euros.

If money isn't indeed the reason for Ronaldo's tears, is it a perceived lack of institutional support at his Madrid club? Does the world's second-best footballer (ouch!) really need a bunch of fat corporate honchos to validate God-given talent and perfection achieved over years of hard work? With no disrespect to Andres Iniesta or his prematurely fading hairline, is Ronaldo upset that he was beaten to the UEFA Player of the Year award by someone more ordinary looking than him?

Or, as some of the jokes online suggest, did Ronaldo's son - the vainly named Cristiano Ronaldo Junior - mistakenly ask daddy dearest for an autograph of Barcelona star Lionel Messi? Is the little boy inside Ronaldo screaming for a bit of love and attention? Or is he unhappy that other Spanish clubs don't get as much TV money as Madrid or Barca? Long shot, that last one.

Whatever it is that's making Ronaldo sad, it seems to be a virus that affects the modern footballer. Cesc Fabregas, Barcelona's talented, long-lost son who returned home or just another football mercenary - depending on whether you are from Catalonia or London - has become an increasingly unhappy figure on the bench. After quitting Arsenal to reunite and rule the world with his fellow La Masia grads, Fabregas has slowly discovered after the departure of Pep Guardiola and the arrival of new coach Tito Vilanova, that playing a bit-part role is inevitable in a club like Barca and the best dreams too can turn sour.

While Ronaldo chose to express his displeasure by turning into the Incredible Sulk on the pitch, Fabregas told the press of his unhappiness while on national duty and said that he would take his 'unhappy' face home rather than subject his teammates to it. Moping alone may not make a huge difference as Fabregas is certain to learn. He's in a team full of superstars who ensure he's unnoticed anywhere anyway.

Carlos Tevez, Manchester City's version of Ronaldo minus the looks and the talent, has frequently talked of his sadness and loneliness at his club before doing his usual flip-flop after a trip back to his native Argentina. All this is followed, invariably, by him grinning his sheepish grin. Even the most devoted City fans probably feel he's one footballer who's better off caddying - as he recently did for pal Andres Romero at the British Open this year.

Yes, the modern footballer has a thing or two to learn from many of the greats of the past and some present stars who played all their lives for just one club. The likes of AC Milan's wall at the back of defence Paolo Maldini, Dynamo Moscow goalkeeper Lev Yashin, Southampton wizard Matt Le Tissier or even present greats such as Manchester United duo Ryan Giggs and Paul Scholes or Spanish stalwarts Xavi Hernandez and Iker Casillas, who have dedicated their lives to the pursuit of excellence at one place.
These are players who have aged like wine rather than choose to whine their way through an unfulfilled career from one club to another, a process which usually starts with the declaration of unhappiness. Where are the players who believe in a system and look to improve it rather than extract the most out of it and move on? Perhaps they don't exist or aren't relevant in today's sports scenario anymore.

Or perhaps there's only one man and his tested way that can really sort out someone like Ronaldo. Is it time to call Sir Alex Ferguson, much more mellow now as he approaches the twilight of his own managerial career, and get him into hair-dryer mode just one more time?