A great signing can be the difference between failure and success. Whether it be Sergio Aguero at Manchester City, Andrea Pirlo at Juventus or N'Golo Kante at Leicester, we love to see a signing who comes in and makes an immediate winning impact.
But let's be honest - the signings we really remember are those which go horribly wrong. For every Cristiano Ronaldo there's a Juan Sebastian Veron, for every Didier Drogba there's an Andriy Shevchenko, and for every Fernando Torres there's a...erm...Fernando Torres.
So remind yourself of these 30 transfers (since 2000) which the men in question would rather forget.