Manchester United have pulled off plenty of transfer coups.
Their history is peppered with stories of players who arrived at Old Trafford and achieved great things.
But for every Eric Cantona, there is a Bebe. For every Cristiano Ronaldo, there is a Ralph Milne.
For every success, there has been a failure.
Here's a list of United's top five transfer mistakes. Weight has been added for the fee paid and their impact. Or lack of it.
Feel free to use the comments section below to agree, disagree and add your own.