As Paul Pierce has said, even though he has left the Celtics, Boston will always be a part of him. The latest example of this is an advertisement for Dish, where Pierce speaks with a Boston accent pronouncing various words. You can see the video here.
At the end of the video, Pierce briefly mentions Brooklyn and the Nets, pronouncing “Brooklyn Pizza”.
My guess is that this ad was planned in advance before Pierce was traded to the Nets. Now, it doesn’t really make sense because Paul is not on the Celtics anymore. Still, he played in Boston for 15 years and Boston will always be a very meaningful place to him.
Pierce was emotional during the press conference announcing his trade to Brooklyn and still probably has mixed feelings about leaving Boston, the team that drafted him and the team he wanted to retire with. But he understands that if the Celtics kept their core together, although they would probably make the playoffs, they would not be competing for a championship, which is what Pierce is looking for at this point in his career.
Now with Brooklyn, Pierce and Garnett and join forces with Brook Lopez, Deron Williams, and Joe Johnson and Pierce believes he will have one last shot at a championship.