Every action has a chain reaction, and we have seen that very much during the now closed summer transfer window.
Many have pointed to Real Madrid's acquisition of Gareth Bale for a world record fee as the move which led to Mesut Ozil being sold, but it was purely the final straw rather than the root cause.
Ozil's discontent had begun earlier, weeks before Bale sealed his transfer.
In Real Madrid's opening league game against Real Betis, Ozil was played out on the right wing, as Carlo Ancelotti shuffled his pack.
The man who grabbed the winner that day was Isco, signed from Malaga for a fee of £23 million.
He has so far been Madrid's main man so far this season, netting three goals in three games, and providing one assist. That's two goals more than Cristiano Ronaldo.
Isco is seen as Madrid's creative fulcrum, and fitting him into the side has been Carlo Ancelotti's priority.
The Spaniard is versatile and can play a variety of roles. He began the season in a deeper midfield position, but once fellow new signing Asier Illarramendi recovers from injury he will be moved forward.
Isco has also started on the left-wing, and through the middle in attack. It is envisioned this could well be the role he excels in, especially now Mesut Ozil has departed.
Carlo Ancelotti decided not that he did not have faith in Ozil, simply that his system was not best suited to both Ozil and Isco. It was the Spaniard's versatility and willingness to track back which saw the former Chelsea boss make the decision to sign off on the sale of the German.
Not everybody is happy at Madrid, and even Isco expressed his shock. It piles a huge amount of pressure on him, pressure he did not necessarily need given the way he has started the season.
It all makes you wonder how it would have worked out had Manchester City been successful in bringing Isco to the Etihad. In one of the early summer transfer sagas, Isco was poised to follow former Malaga boss to Manchester, before Zinedine Zidane stepped in and convinced him to join Madrid via a personal phonecall.
Up until that point, Isco has previously admitted he was bound for the Premier League.
Had City secured the deal, either acted quicker, or come up with a more attractive counter-proposal, there is every chance Mesut Ozil would not now be an Arsenal player.
Ozil was allowed to leave because there was a new creative midfielder in the side. It's unlikely Madrid would have simply 'gone and bought another one', as there simply are not many players of Isco's quality which come onto the market every summer.
The fact he is Spanish made him a 'must-sign', with Ancelotti determined to give his Madrid side an Iberian identity, lost at times in the Galacticos era, and one harnessed by Barcelona.
The Madrid project is a fascinating one to follow, especially with Gareth Bale added to the ranks. His versatilty allows him to drift inside and Isco outside, whereas Ozil would have ideally stayed central.
The summer was full of twists and turns, and the butterfly effect which led to Arsenal signing Ozil was one which allowed only a small margin for error. Had Manchester City been successful in signing Isco, it's likely Arsenal would not have their most exciting addition in a generation.
image: © Klapax1