I really enjoyed Cars 2 and I have a theory regarding the story, specifically Mater's point in the movie. I apologize in advance if this is a little ridiculous and farfetched and I also apologize if someone had the same idea in this thread (although I doubt it). I didn't read every one of the 400+ replies, so forgive me.
Cars 2 may be Pixar's most introspective movie to date. It's a gorgeously crafted, fast-paced, and funny movie, but it's one that explores Pixar's own view of the Cars franchise and how they view the critics of both Cars and Cars 2.
Let me explain.
[Show spoiler]One should know I didn't spin this theory until about two-thirds of the way through the movie. It was one scene in particular: When Mater is tied up, unconscious, reliving some of the major moments in the film. He's seeing all the times when his humor became a sore point for other characters, specifically Lightning McQueen. With a pitch black background, encapsulated versions of these scenes whirl past, left and right, and Mater is seen reacting to each with bewilderment and then horror. He is then presented with a mirror (a very common image of self-reflection in cinema), he looks at himself and, for the first time, realizes how everyone else in the world sees him.
He's taken aback. What he first thought was harmless fun (Getting distracted in the middle of a race, mistaking wasabi for ice-cream, etc.) he then sees as distractions that bring stress to others. Afterwords, he wakes up to see that he's about to meet his demise in Big Bentley along with Finn McMissle and Holley Shiftwell. In the scenes that follow, he uses his knowledge of automobiles, as he's been towing them his whole life, to rescue the two, and later Lightning and the gang, and get everyone out of their respective predicaments (some of which he created).
That cathartic scene of Mater and the mirror represents Pixar doing their own self-reflection. They were, in a way, looking at the Cars franchise, and how critics easily degrade the comedy of the series as "childish," "annoying," and even "distracting." Ultimately, though, what Mater discovers (after Lightning realizes how big of a douche he's been) his how his comedy is a bit brash, but that it really shouldn't change. Who cares if others look at you weird? Just because they don't see the heart and the brain you have, buried deep inside, doesn't mean it isn't there.
Like McQueen says to Mater directly, it's not you who needs to change, it's us. That's Pixar speaking directly to the critics (very much the antithesis of the message they sent in Ratatouille) and saying, we don't care how you view the Cars franchise. We make these movies because we believe in them. Like Mater, our stories have a heart and have powerful themes that can reverberate with many people. The viewer might not notice these things at first (just how Lightning doesn't with Mater) but that doesn't mean they aren't there.
Cars was Lightning McQueen's movie and Cars 2 is undoubtedly Mater's. Critics have derided the movie for having too much of his comedy, but (if you think my reading of the movie has any weight at all) it simply wouldn't work without that comedy. The climatic scene would have no heft to it if the silly actions of Mater weren't there to back it up.