Regarding him not doing voices for fans, he's often said that the characters are too precious to him for him to just do the voices when fans ask, feeling it cheapens the characters a bit. Though I remember seeing one interview (I think it came out around the time of Star Wars Episode III, or maybe when Death at a Funeral was in production) where he said that when members of the cast and crew of his movies ask, he'll tell them he'll only do the voices for them on the last day of filming (but what if it's somebody who won't be there on the last day?), having said something about doing so otherwise would cause the cast and crew to not take him seriously enough as a director. And I've seen a clip of Oz on The Today Show in the early '80s where the person who interviewed him asked him to talk in Cookie Monster and Grover's voices having a conversation, which he obliged. But maybe he didn't feel that way about the voices back then. I don't think he said anything too bad about the movie or the company.