Idea stolen from Dexter's Laboratory
I've never liked this film before, but now I have found another reason why not to like this movie:
I just watched an episode of Dexter's Laboratory and the idea/presentation of a talking dog was very similar. Anyone reading this who wants to see for themselves should check out the episode, Dexter's Lab: A Story (first aired in January 1998). The only difference is Dexter uses a pill, while in Up an electronic device is used. The end result/gag is too similar for my taste, especially since it was such an integral part of the comedic element of Up.
Up, along with The Incredibles, have always seemed highly unoriginal to me. I love much of Pixar's other films, but these two were unfortunate disappointments.