Old Trafford has served as a platform for some of the world's promising starlets to emerge from their cocoon and spread their wings. The club has reaped the rewards from the faith shown in enticing the world's most exciting youth to Manchester, and through investing large quantities of cash in various world-class superstars. However, like every football club, there have invariably been a host of players who have served only to cause the manager endless migraines, forsaking their talents for excessive salary demands, unprofessional behaviour or simply more time spent in the infirmary than on the pitch. It takes time and effort to finalise big money transfers, or even to coax and prize young starlets away from their parent clubs. One that player is handed a pen to sign on the dotted line, with a beaming manager posing with him for a press photo, a mutual trust is expected to be shared. When that bond is broken, it can sometimes get a little bit messy for all concerned. Sir Alex Ferguson has already lynched a couple of players in his cutthroat autobiography. Here are ten players who caused the club more trouble than they were worth. Sometimes, the Manchester United chiefs must just wish they hadn't bothered.