#1 - George Best:
It is common to hear among Manchester United fans, that George Best is the greatest player to ever wear the red shirt, which could lead you into questioning his presence in this list.
While it is true that Best guided United to two English league titles, as well as to a Champions League triumph in 1968, what many don't know is that Best took the decision of retiring from football at the young age of 25.
He eventually reversed his decision and continued being part of the club up until 1974 before giving up for good.
After leaving United, Best played for 16 clubs in less than 10 years, and as you can guess, he didn't even show anywhere near the talent he once possessed.
At his best, George Best was the best player in the world, who could do it all. From spectacular Maradona-esque dribbles, to fantastic finishing. He was the definition of the big-game player, but his tendencies of following women and alcohol ruined what could have been an even more legendary legacy.
It is hard to predict what Best could have achieved if he took training more seriously and was more professional throughout his career.