Arsenal fans will never forgive Cesc Fabregas for joining a Premier League rival from Barcelona, even if he wasn't given much choice.
Back in 2014, the Spaniard moved to Chelsea in a £30 million deal after Arsene Wenger rejected the chance to resign him.
And the reason? Because he already had Aaron Ramsey and Mesut Ozil.
Fabregas revealed as much in an interview in 2014, saying that Arsenal had first choice to bring him back to north London but said no.
"When I decided that my time at Barcelona had ended, I looked for the best option for me," the 30-year-old explained. "Arsenal was the first option, for contractual reasons.
"There was a clause that gave them the right to decide. We spoke to Wenger and he said that the space was very well filled by Mesut Ozil and it was hard to find a place for both of us in the team."
Arsenal fans may dislike Fabregas, but they'll agree that passing up on the chance to resign him was a big mistake on Wenger's part.
In his eight years at the club, Fabregas developed into one of the world's finest central midfielders and even earned the captain's armband.
He owes a lot to Arsenal and earlier this year he explained that the club will forever hold a special place in his heart.
"Yes, forever," Fabregas admitted. "There are some things that will never change. Arsenal will always be the team that believed in me the most.
"I was a young kid, playing for the Barcelona academy - where it is difficult to reach the first team - and Arsene Wenger especially gave me everything."
Fabregas provided Arsenal fans with some great memories during his eight-year stay and now he's revealed a brilliant story about when he abused a certain Harry Redknapp.
Speaking to James Corden on the latest episode of 'A League Of Their Own', Fabregas recalled telling Redknapp that his Portsmouth team played "like s***" after a 0-0 draw in 2007.
Take it away, Cesc.
"It was at the end of a game with Portsmouth and it was a nil-nil," said Fabregas. "I was young and you know, stupid.
"I want to win and I just saw him there in the tunnel of the Emirates and I just said: 'Your team plays like s***'.
"And he just turns round and says: 'You are a horrible man'. I just run away. After that, we've been best friends. Every time we see each other we hug, we talk."
If only Redknapp was Tottenham manager at the time...