Conversational, Childish, Ironic
Viorst's narrative voice is filled with: the reader is constantly aware of how ridiculous Alexander sounds in his overly dramatic take on the events of the day. From the moment Alexander wakes up with his own gum in his hair, tripping over his own messy room, the audience knows something that he doesn't: he's being unreasonable, and some of this is his own doing. With that irony comes humor that resounds throughout the book.
The stark contrast between Alexander's interpretation of events and our own "reasonable" second opinion actually allows readers—parents and children alike—to evaluate and take stock of Alexander's reactions. For children, especially, it's really hard to step outside of ourselves and reflect on our actions and feelings. For most of early childhood, they are what developmental psychologist—and creepy old dude extraordinaire—Jean Piaget called "egocentric," meaning that they are the center of the world, and they can only think about things from one point of view—their own (though to be fair, it often feels like adults still act like this, too).
Alexander is not only the perfect example of this struggle, but also fodder for readers to reflect on the very same feelings that they can't peel away from in themselves.