4. Ronaldinho
Destination: Barcelona It was a pretty long-winded saga 10 years ago in which United relentlessly pursued Ronaldinho (10 years, where does the time go?). The deal seemed so certain that you would have been forgiven for going out and getting Ronaldinho on the back of your United shirt. But PSG announced the player would instead go to Barcelona for £21million, citing United's arrogance in negotiations as one of the reasons they sold him to the Spanish giants instead. It is impossible to know, of course, whether or not Ronaldinho would have set the world alight at Old Trafford like every United fan so craved. But I think if you look at how it worked out for both parties, United and Ronaldinho would say things turned out alright for them. Ronaldinho went on to become undoubtedly one of the symbols of footballing greatness in the past decade; FIFA world player of the year twice, acting as a catalyst for a new wave of success at Barcelona. Meanwhile in the same summer that United missed out on him, a spotty teenager called Christiano Ronaldo arrived at Old Trafford... Ronaldinho has since then, pretty recently in fact, stated that United would have had more European glory had they signed him. Whether that means he regrets missing out on a chance to play for them only he will know. Sources:
BBC