How we cite our quotes: All quotations are from WALL-E.
Quote #1
"Out there, there's a world outside of Yonkers, way out there beyond this hick town, Barnaby, there's a slick town Barnaby. Out there, full of shine and full of sparkle, close your eyes and see it glisten, Barnaby."
We don't know who Barnaby is, but this song from Hello, Dolly is the first thing we hear when WALL-E begins, with a wide shot of a ruined Earth. It gives us a feeling that we're going to see more than just Earth in this movie. These lyrics, when put against the backdrop of space, pretty much cements the fact that we're going to leave Earth's atmosphere before we know it.
Quote #2
"There's lots of world out there […] We're gonna find adventure in the evening air. Girls in white in a perfumed night where the lights are bright as the stars."
Okay, one more bit of exploration-based foreshadowing. A girl in white, eh? Well, we're going to find EVE, who is a girl in white. She's made of white plastic. And we do see some pretty bright stars—actual stars.
Quote #3
[WALL-E plays with fire extinguisher after finding it in a garbage heap.]
WALL-E doesn't just compact trash like he's supposed to, he plays around with it, tinkering with it, and figuring out what it does. When he squirts himself in the face with a fire extinguisher, he figures out that he wants nothing to do with it, but it comes in handy later when he uses one to propel himself through space, something he'd never be able to do if he wasn't so curious.