Costa has been in sparkling form so far in 2016-17, rediscovering his best under the tutelage of Antonio Conte.
But it could all have been so different had the Spain international followed through on his wish to work under former mentor Diego Simeone again at Atletico Madrid.
“Could I have gone in the summer? Yes, yes. I was about to leave,” he said. “I was about to but, well, I’m happy here as well and that’s that,” he told reporters.
“Did I want to go? Yes, yes. I had the possibility to go to Atletico, because of a few things, the family, the life I have there but not because of Chelsea, because, here, there’s a lot of love with the supporters, with the people, so I’m here very happy, I’m very content.
“People love me a lot. There was one thing I wanted to change for family reasons but, well, it wasn’t to be and I continue to be happy here. It was important too that the manager, from the very first minute, said he counted on me.
“The truth is the manager is good with the players, every time making more jokes with the players, and that’s good for us, to have a manager who is not just a boss but like a person we can talk with, someone whose support we can count on in difficult moments. He is calm with the players and you can see the people love him more all the time.”
While 14 goals in 18 Premier League games have caught the eye so far, Costa insists that he is also delighted with his improved disciplinary record.
“I know what I have to do. I know when I do bad, so I thought about it and knew I had to improve that aspect because, here in the Premier League, the reality is there’s no mercy [authority], a lot of the time it seemed like they [referees] were against me,” he explained.
“There was no other way, because if they’re not going to change, I had to change.”
Costa currently leads the Premier League scoring charts, while his club sit pretty at the summit six points clear of nearest rivals Liverpool.