Since leaving City, Boateng has won the Champions League and World Cup.
He told the Mail on Sunday: "I was young. My girlfriend was pregnant, we wanted her to stay in Germany and have the baby there. Then I started with a knee injury. The coach promised that I'd play central defence - but I played right, I played left.
"Then I had another knee injury, I had an operation also, so I was not happy with the whole situation. And then Bayern came.
"But I learned so much, even in training, from the players there. That's why I made the move - Vieira, Kompany, (Carlos) Tevez, (Emmanuel) Adebayor at this time - they are all great players. So I learned a lot about myself also and they gave me good advice and that's why I say I'm not sad that I went to Manchester."
For the big stories and the banter follow us on Twitter: @tribalfootball