In world football, one event often sets off a chain of events. One team's failure leads to another team's success, which impacts another team, and so on and so forth.
For example, Liverpool's inability to reclaim its usual Champions League spot last season meant that Manchester City made it into the Champions League in their place (just ignore that Arsenal conceded third place for now).
That meant that Manchester City became a more attractive destination for players to transfer to, while Liverpool became significantly less attractive.
What happened? Samir Nasri, Gael Clichy and Sergio Aguero all jumped on board the Manchester City train and made the squad even stronger, while Liverpool was left to recruit EPL players from weaker clubs.
Would this summer have played out the same way if the roles had been switched, if Liverpool had finished in the top four and Manchester City had finished sixth? I highly doubt it.
Sure, money always has its pull, but both Clichy and Nasri were, according to their personal accounts, drawn by the opportunity to win silverware. The same applies to Aguero, who had many suitors to pick from in the summer.
Extending this further, Liverpool's failure and Manchester City's success impacted Arsenal heavily, because had Manchester City had a poor season, Nasri would've likely preferred to stay on with Arsenal for at least another season.
This is how world football works. One event plays into many others.
With this concept in mind, let's now look at how Carlo Ancelotti's appointment at Paris Saint-Germain will impact various players, coaches and teams in world football in the coming weeks.