You don't "hear it" but it's obviously there. Chances are you can imagine a random animated movie, take its screenplay just as it is and apply it to a live action film - more than likely it will come across as just another shallow comedy/ action movie/ rom com/ adventure movie etc etc. Critics would have shreded a movie like this but because it's an animated movie, it's "ok".

Toy Story 3 is pretty good but I think it dwells too much on different concepts. I just wish they'd focus more on one thing - as it is, most of the movie feels like "filler content", with some genuine good ideas that are just barely addressed or done so in a very shallow manner. Toy Story 1 is like the perfect solution - it's very tight, very controlled and wholy inspired and focuses on one thing (the condition of a Toy's life, reflected in Buzz and Woody's rivalry and the whole journey). Toy Story 3 is about Andy leaving and about being forgotten and while a lot of the movie accomodates to this (Lotso's story as a contrast, Bonnie as a new home, even the concept of the kindergarten which poses a different idea of being played with) most of it is just... filler, you know what I mean? Most of the character's reactions to being forgotten/ played with again/ brought to a new home are brief or non existent; conversations are very linear and expositional; moments that could be spent on developing the subject are wasted on gags (funny and well made, but still); most of the things that could be interesting (the kindergarten, the incinerator, Bonnie, even Lotso's story and perspective) just come out as mechanics to move the plot forward into scenes that you can tell the director(s) really wanted to make and address.

With that said, it does not make Toy Story 3 a bad movie by any means. Most of this "filler" content that I speak of is still very enjoyable, but it definitely makes for a less tight and well rounded movie (again, for a good example of this just rewatch Toy Story 1). And the Oscars are about awarding the absolute best - Toy Story 3 is not even close to the absolute best.