The character Joy describes Fear as the one who keeps Riley safe, while showing Fear prevent Riley from tripping over a wire. This is just one of many moments throughout the film that prove how sometimes in this world, happiness may not be the most appropriate response. In fact, that's what the whole story arc is about. Joy and Sadness are swept out of headquarters and must work together to find their way back. Meanwhile, Anger, Disgust, and Fear are the only ones left to help Riley navigate the difficulties of moving to a new city and trying to find her place there. The separation between the characters makes clear how all of them are needed for Riley to be, well, Riley. Now that I'm writing it out, the message by itself seems a little corny, but the movie did a great job in not becoming fake or sappy. I even cried. Twice.
We also get brief glimpses into other people's heads, which usually led to a lot of crack up-worthy moments (by the way, can I get a Brazilian helicopter pilot to daydream about?). One thing bothers me about that though: the emotions get the same hairstyles as the person whose mind they're in, except for Riley's. Her dad's emotions have his mustache, and her mom's emotions have her ponytail. Riley's emotions, however, have nothing in common in their appearance. It's a small thing, but consistency-wise it is questionable when you really think about it.
My tangent aside, Inside Out is a beautiful, funny, and meaningful movie that deserves all the critical praise it has received thus far. This is just my two cents, but I think anyone who likes Pixar will definitely like this movie.