Chelsea's reckless decision-making at the top often leaves supporters pulling their hair out and this is particularly poignant in their transfer dealings.
Given their size and stature as a footballing powerhouse, the Blues are unsurprisingly able to attract some of the world's biggest talent, yet one notable issue has been their decision to let go a number of other high-profile talents.
The list of world-class stars that the club have let depart over the years is endless, letting go of Declan Rice as a youngster, Kevin De Bruyne in 2014 and Mohamed Salah in 2015.
What's more alarming is the fact that Chelsea have also sold quality talent to their rivals without thinking of the consequences and strengthening them in the process.
Juan Mata is the prime example of this ineptness coming into fruition with the Blues having sold him to Manchester United in 2014.
Prior to sanctioning this ludicrous transfer, the Spaniard was one of the best attacking midfielders in the league and rose to prominence at Stamford Bridge as an assist machine.
The price Chelsea paid for Juan Mata
Mata rose to prominence as a midfield metronome at Valencia in 2008 and his playmaking abilities, in particular, propelled him close to the level of sensational midfield duo, Xavi Hernandez and Andreas Iniesta, who were forming one of the greatest partnerships to grace European football at Barcelona.
During the 2008/09 campaign which saw Barcelona dominate world football, Mata's domineering performances in La Liga set Spain alight. In 37 appearances, the fleet-footed attacking midfielder supplied an eye-watering 11 goals and 17 assists.
Ultimately, the Spaniard's exceptional abilities as the ideal modern playmaker earned him a £23.5m move to Stamford Bridge in the summer of 2011 after posting 98 goals in 174 matches for Valencia.
The diminutive and fleet-footed attacking midfielder was already on his way to becoming one of the best talents in world football, but after an outstanding debut season in England – which saw him contribute a remarkable 12 goals and 20 assists in all competitions, lift the Champions League, FA Cup and earn a nomination for the PFA Player of the Year award – Mata was on top of the world.
That exceptional individual campaign was somehow exceeded in the following year as the 5 foot 7 wizard conjured up more magic to help Chelsea lift the Europa League whilst recording a staggering 54 goal contributions in 64 matches, including the most assists in one season since the 2000/01 campaign (34).
(0 goals, 2 assists)
(20 goals, 34 assists)
(12 goals, 20 assists)
Mata reached the pinnacle of world football at Chelsea, smashing several records, lifting a whole host of trophies and was the future of the Spanish national team, but that didn't stop Jose Mourinho from selling him to rivals United for £37.1m in January 2014, with the Portuguese later revealing the reason why a deal was sanctioned.
He told the Telegraph [via the Daily Express] in October 2014: "in the modern football and the new economic reality [for Chelsea], if Man Utd pays you an important amount of money he has to go.
"It is my club's vision. It's my boss, Mr Abramovich, the board. And I share it."
Juan Mata's time at Manchester United
Mata was signed for the Red Devils in a time of transition and was brought into the club by David Moyes, who described him as "one of the finest playmakers in the game today".
A real coup for the club at the time, the acquisition of the 25-year-old promised to deliver United endless amounts of success – after all, they were still used to being a trophy-winning machine under Sir Alex Ferguson.
Mata arrived at the club having won back-to-back Player of the Year awards with his previous employers, as one of the finest creators to grace the competition having supplied more assists in his time at Chelsea (57) than he managed in the rest of his decade-long stint in English football.
However, the "magician", as described by Michael Carrick, was denied legendary status in the Premier League through Red Devil mismanagement and ill-thought-out strategy.
He fell victim to the toxic rift at the club that was created after Ferguson departed, clinging onto the obsession of maintaining a style of football they’ve never got close to matching.
Unfortunately, after departing Chelsea, Mata never reached the ceiling of this potential – and that wasn't down to the individual himself – it was the constant chopping and changing of managers, wasting millions on talent and playing without a recognised style that prevented the Spaniard from replicating his sensational Chelsea form.
He would go on to make 285 appearances for the club in eight and a half years, returning a respectable 51 goals and 47 assists, departing for Galatasary in 2022 – for whom he provided a further three goals and two assists – while now plying his trade in the J-1 League with Vissel Kobe.
When looking back on his career, supporters are left to imagine what the World Cup-winning, Champions League-lifting and assist-making machine could have achieved if he hadn't been held back by the toxicity that broke out in the post-Ferguson era at Old Trafford.
As for the Blues, it is hard argue that they ever truly replaced the Spaniard in that number ten berth, with even Eden Hazard's best season for the club – in which he registered 37 goals and assists in 2012/13 – not coming close to Mata's heroics in that same campaign.