Andrew Staton was the first person to come up with the idea of having a movie completely immersed in the idea of a robot love story. This idea joined two of his favourite elements, space movie genre and giving life to inanimate objects. ”What if mankind evacuated Earth and forgot to turn off the last remaining robot?" After explaining his idea, Docter did additional work on it for a couple of months in 1995 but decided to move ahead with Monsters, Inc. as he was unsure of telling a love story. Despite this Stanton continued to play with the story.
Wall-E is self-sufficient and free, and therefore enjoys his programming even though it’s a monotonous, dirty job. Status means nothing to him and Wall-E’s environment reflects back to him his value and importance.
Wall-E was chosen because it was an easy way to educate, not only children but also adults, about environmental problems and what is may come to, although overly exaggerated.
The design of WALL•E came from Luxo, Jr. and a pair of binoculars that Stanton was playing with at an A's baseball game. He noticed that he could demonstrate emotions such as happiness or sadness by just moving the binoculars, or the eyes, up or down - that it wasn't necessary to have other parts of the face like a nose or mouth.
This idea was expanded upon because despite coming from a question it was a good idea. It would be killing two birds with one stone. It would be teaching people about environmental issues and in the end it would be a great movie that is still watched eight years later, so they are still consuming money from the movie.