#3 Sol Campbell - Tottenham to Arsenal
One can imagine how much pain Sol Campbell caused Tottenham Hotspur fans when the latter publicly declared the English centre-back as 'Judas'.
Campbell completed nearly a decade at White Hart Lane and was a cherished personality at the club, loved by all fans and fellow players alike. When he decided to join Arsenal, it shocked the entire football world, especially the Tottenham fans.
The move was considered treachery as the Gunners were Spurs' fiercest rivals, and Campbell had said earlier that he would never play for Arsenal.
The rationale for Campbell's decision was simple as the footballer wanted to play in the UEFA Champions League and challenge for trophies. He immediately found success as the hard-hitting defender became a mainstay at the back for the Gunners.
In his first season, Campbell's decision bore fruit as Arsenal won the domestic double - the league and the FA Cup. Campbell spent five seasons at Arsenal and left as an 'Invincible' after winning the league undefeated in the 2003-04 season.
#2 Robert Lewandowski - Borussia Dortmund to Bayern Munich
Bayern Munich have often been accused by detractors of pillaging the Bundesliga by acquiring the best talent from fellow title challengers. The accusation gained ground after the acquisition of Polish superstar Robert Lewandowski.
Lewandowski's departure had left the entire Borussia Dortmund fanbase heartbroken. The feeling has gotten worse over the years as the forward has grown even further to become one of the best footballers in the modern era.
From Bayern's point of view, Lewandowski's free signing has been a terrific one. It is his eighth season with the Bavarian club, and Lewandowski is a goal-scoring machine.
Aside from his first season at the Allianz Arena, Lewandowski has scored 20+ league goals every season and is already nearing the tally in the current season. He has won several major trophies with Bayern Munich, including the highly coveted Champions League.
#1 Lionel Messi - Barcelona to PSG
Lionel Messi's departure from Barcelona was not only a completely unexpected one, but the reason is quite different than that of the other four on this list.
Barcelona found itself with a massive problem in the summer of 2021 with an inflated wage bill. They needed to reduce their wage bill before registering any new signings or contract renewals. Messi's contract with the club expired at the end of the 2020-21 season, but talk of a renewal seemed positive.
However, a resolution didn't arrive in the end and Messi joined PSG after a long saga spanning all summer.
It can be said for certain that the move has caused much pain to the Barcelona faithful. Messi had grown up and become everything he is today in Catalonia. Although it's just speculation, Messi would still have been at Barcelona had it not been for the wage bill issue.
It's still acceptable when a player leaves out of his own volition but that can hardly be said about Messi's move. The transfer was evidently crushing for both the fans and Messi alike, as he bid a tearful adieu.