Five of the worst: Transfer mistakes
Andy Carroll, Gerard Pique and Juan Mata - five of the worst transfer mistakes
The transfer window makes people do strange things. Like spend £35m on a "big bugger" who's good at heading and jumping.
Logic goes out the window - panic buying, a phenomenon that's all too common at this time of year, becomes the norm.
Club executives prowl the boardrooms, manager's hole up inside their offices, or lurk in their cars with their windows rolled down, and the ancient system of communication known as "the fax" suddenly becomes popular again, like everyone's just forgotten about it for the past 15 years.
Deadlines encourage procrastination - any student knows this. And what is a transfer window if not one mad dash to finish a dissertation in one hysterical night of panic. Only football has Sky Sports' Jim White to squeal commentary while wielding a giant iPad.
Inevitably, anything done "against the clock" will lead to mistakes. Forget to attach the bibliography, miss the glaring typo, overlook the fact you've completely failed to address the question. University students make them all the time, and so do football clubs.
Some disastrous decisions have not been the result of a club's last-minute, panicked choice. They've just miscalculated, perhaps misjudging a player's future potential, or their current worth.
Twenty years ago this week, Manchester United signed Eric Cantona for just over £1m - comfortably one of the greatest signings of all-time. But even Sir Alex Ferguson is not immune. Even Fergie has shanked a few into row Z - Eric Djemba Djemba, Juan Sebastian Veron and Ramon Van Der Gouw spring to mind.
Hey, everybody makes mistakes. Here, GMF looks at some of the biggest…
Gerard Pique - Manchester United to Barcelona
Pique's return to Barcelona was not the result of a frantic decision made against the ticking clock of a transfer window - instead, it was a simple misjudgement.
Sir Alex Ferguson has admitted he had too many quality centre-backs - Rio Ferdinand was a fixture, Nemanja Vidic had just signed, Wes Brown, John O'Shea, Jonny Evans competed for playing time, while Mikel Silverstre warmed a seat on the bench. The United boss even had high hopes for promising youngsters Craig Cathcart and Ritchie De Laet.
Pique, who had been at United since 2004 and had only made 12 league appearances, was restless for first-team action - something Ferguson could not guarantee.
So, he sold Pique to Barcelona for £5m, and the Spaniard has become a double European champion, a World Cup winner and one of the best central defenders in the world. John O'Shea and Wes Brown went to Sunderland, Richie De Laet to Leicester City and Craig Cathcart to Blackpool. Mikel Silverstre was released. Whoops.
Andy Carroll - Newcastle to Liverpool
This is a classic example of misjudging a player's worth. If you spend £35m, you can reasonably expect to sign a world-class player. Tens of millions of pounds should guarantee that, at the very least.
Eden Hazard, Lucas Moura, David Villa, Wayne Rooney and Didier Drogba were all signed for less, and Andy Carroll's best will never reach close to the maximum ability of these players.
Liverpool made a huge reach, and came up horribly short.
Yaya Toure - Barcelona to Manchester City
The Ivorian was a big player for Barcelona, but the Catalans thought they were getting a great deal when megabucks Manchester City turned up to the Nou Camp and offered £24m.
But Toure has only improved since signing for Roberto Mancini's side. Last year he was instrumental as they won the Premier League title, and particularly shined in an advanced midfield role. £24m is a lot of money, but Toure has proven to be worth every penny.
Ashley Cole - Arsenal to Chelsea
Everybody knows the story behind the Ashley Cole transfer, so while it's never a good idea to get bad news on the phone while driving, there's no doubt Chelsea got a great deal from Arsenal for the England left-back.
£5m plus William Gallas is a small price to pay for a player who was to become one of the best players in his position for the next six years.
Juan Mata - Real Madrid to Valencia to Chelsea
The Chelsea playmaker is one of the best players in the Premier League, and would have been strutting his stuff for the La Liga champions had they not tossed him aside as a 19-year-old in 2007.
Since then they've spent £30m on Luka Modric, £56m on Kaka, and £13m on Mesut Ozil. They had a player as good on their books all along. Valencia got the best deal, but Chelsea can still be pleased with their business - Mata was signed for close to £20m in 2011. An expensive mistake for Real Madrid.