Transfers that make total sense for all parties rarely occur in modern football. There are too many egos to impress, sums of money unthinkable to count at play and simply everyone looking to gain an advantage.
Selling clubs do not always want to let their players go. Buyers are not keen to over pay, wages cause issues, agents are added obstacles to bypass and there's now more and more PR at play.
Chelsea and Arsenal have managed to hit the spot with their latest negotiations. In recent years the moves for Petr Cech, David Luiz and Willian have been all in Chelsea's favour. Pierre-Emerick Aubameyang, via Barcelona, was a rare win for Arsenal in these transactions but going back it has rarely benefitted the Gunners.
