Yakubu said: "I wanted to move to a club which had ambition and at the moment Everton have ambition. They are fighting for trophies and they want to finish in the top six and play in Europe.
"Before I left Portsmouth I looked at Middlesbrough and saw they had ambition, but I don't think the ambition is there any more. With no disrespect to the players, Middlesbrough are not that ambitious and that is why I had to leave.
"Before the end of last season I had made up my mind to leave. It was a blow to lose Mark Viduka, because he was a great player who I enjoyed playing with. He is a great person, too. I wanted to carry on playing with him but it was not possible.
"I would not say anything bad about their players, but I just wanted to play for a club that was in Europe and I am enjoying my football at Everton. I am lucky to be there. I am really happy.
"We are chasing a trophy in the Carling Cup and if we can win something that would be a great season both for me and the club. I moved at the right time and made the right decision to go. I don't regret it.
"It is disappointing when you play for a club, then you leave and come back and the reception is bad. You have to cope with it as a footballer and you have to accept it. And I did expect it."