Though Baradwaj Rangan mentioned (link currently unavailable) that the best part of watching Ratatouille was the animated short, Lifted, that they showed before the main feature, I wasn't paying that much attention.
Just as well, really; because watching Lifted made one feel the way Remy must have felt after chomping on cheese and strawberry and watching the stars dance in his head. Too much attention to the review would have spoilt the joy of the unexpected.
What is really amazing about the film is that - leaving aside all the details of the story - it is about the big guy saying, "Okay, here's all the tech backing you could want. Now show me what you can do." And the short film does show, in no uncertain terms, what it can do.
It says quantities about Pixar's confidence that while it graciously accepts the homage paid to it in the film - where the big guy has to come to the little one's rescue and save the day - it acknowledges that the little guy has what it takes to one day do the big feature, that his talents are worth showcasing, that just possibly some people might leave the theatre having enjoyed the starter more than the main course.
That's one of the reasons why I love Pixar.