"Don't you think it's more likely the entire world grew?"
-Patrick Star, after being shrunk by a shrink ray.
Your first instinct is to go "ha ha, oh Patrick. Of course you and SpongeBob shrunk." For most viewers, that's where their processing of this line ends. Patrick has a misplaced confidence in his inflection that's more than enough to carry the naive interpretation and make it funny.
But then you realize that you're calling shrinking two objects more ridiculous than growing everything else. You're saying that one impossible thing is more impossible than another impossible thing. You have a laugh at yourself because you realize that you just bought into cartoon logic as fact.
But then you realize that Patrick was actually right. Or at least, not particularly wrong. The notion of size only really has a definition in terms of other things. All the ray did was change the ratio of the size of SpongeBob and Patrick to that of the rest of the universe. From SpongeBob and Patrick's point of view, are they any smaller? Does it take SpongeBob less time to move his arm from one side of his body to another? Does Patrick all of a sudden feel lighter? No, of course not. Because of the fact that size is a strictly relative measure, Patrick's retort to SpongeBob's claim that the two of them shrunk is actually valid.
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senorhousemouse