The Brazilian defender returned to Stamford Bridge from French giants PSG on deadline day and is delighted to be back in West London after never getting the chance to say goodbye.
"I think that sometimes the life is great but I was feeling sad when I left, especially because of this – because I didn't say goodbye to anybody," he told chelseafc.com.
"But I can say now that my relationship with everyone here was always amazing, with everyone working here and with the players and I can feel the same respect and the same love now.
"So if I had the opportunity to go back into the past, I would say a special thank you to everybody because I spent three-and-a-half years here and they were amazing.
"I was growing a lot and that is why I just had great memories of here."
Luiz, 29, also revealed that it was his choice to leave Parc des Princes to return to Chelsea.
"It was my decision, yes," he added.
"I really wanted to come back because I spent an amazing time here. I loved to be here and that is why I want to come back."