#2 Fernando Torres (£50m) - Liverpool to Chelsea

Torres was the darling of Anfield once upon a time. He had played 142 games and scored 81 goals for Liverpool since joining from Athletico Madrid. He was one of the most feared strikers of the Premier League, yet in January 2011, after a failed Chelsea bid, Torres handed in a transfer request that rocked Anfield, which was rejected. Torres eventually joined Chelsea from Liverpool for a then British record £50m transfer fee, perhaps taking the most fatal decision of his career.
Even since joining Chelsea, it has been a downward slide for him. He played 172 games for the Blues, scoring 45 goals, but looked a shadow of the once clinical striker that the world revered. He then had unsuccessful loan spell at AC Milan and Atletico Madrid, and has now joined the J1 League side Sagan Tosu.
This is a clear case of one wrong decision that changed your life, only here, it made Torres, the second most costly flop in the football world.