Review of Everybody Loves Raymond: The Last Laugh

As much as I liked this behind-the-scenes show, has no one else noticed that Doris Roberts is in NONE of it, except for the clips? All the other actors are interviewed, obviously over a period of time. All the writers discuss the other actors as well as the characters, with (I think) only one reference to Marie. All are seen backstage, fooling around, except Doris. Even at the end, when Romano hugs each star one by one at the end of the taping of the last episode, no Roberts. I just find this so bizarre. Heaton, Garret, etc., all talk about each other admiringly and lovingly. No one mentions Roberts, who won 4 Emmys for the show and, along with Ray himself, appeared in every episode. What happened?