YA lit's love-hate relationship with categorization

Like many people who grew up with the Harry Potter books, I would often wonder about which of the four houses I would have been sorted into, had I been so lucky as to go to Hogwarts. At first, I thought that my curiosity and love of learning would make me an automatic Ravenclaw. Later, I realized that I "loved" learning in part from a Slytherin-ly desire to achieve certain goals - which wouldn't be possible without a big dose of Hufflepuff perseverance. 

Which is all just a roundabout way of saying that I thought I could be just about anything, except for a brave Gryffindor.

In the last few years, my preoccupation with sorting faded somewhat, although sometimes I would still (silently) sort people that I met. Unexpectedly, a few weeks ago I found myself thinking about these things again as I was reading Red Rising, a young-adult dystopian novel that was published last year and has since become hugely popular. While reading it, I was struck by the layer upon layer of categorization: people's roles in society are color-coded and a single color can have multiple divisions within it. In the most prestigious division of the ruling color, teenagers study at an academy where - echoing Harry Potter - they are further divided into houses based on personality traits. 

Whether all this fragmentation is necessary for the story is debatable. However, Red Rising is far from being the only recent (and super successful) YA novel in which categorization is a powerful force in characters' lives. Two other examples that come to mind are the districts in Hunger Games and factions in Divergent. Whether it results from the location of your birth or from the personality you develop, it seems that membership in some kind of category is a concept that interests a lot of readers - and there are lots of quizzes to help readers find their place in their favorite fictional universe. 

• Inserting yourself in a story. Figuring out which category you belong in can help the reader imagine what it would be like to inhabit the world of the story. It can provoke interesting questions about what qualities you have and which ones matter most to you. 
• Simplifying a complicated, populous world. When a ton of new concepts are being thrown at you, as often happens in these fantasy and sci-fi books, labels can be a shortcut to identifying characters' roles and traits. It's not unlike the way we might label real people. 
• Creating a sense of belonging. Most people, and probably especially the target audience of YA books, want to feel like they belong somewhere. Categorization can be an appealing path towards this goal: you're automatically placed among people who have a lot in common with you. 

At the same time, categories often turn into barriers that the characters must find ways to get past. 

• Restricting what you can do and where you can go. In Harry Potter, being in one house means you couldn't enter other houses' common rooms. More starkly, in Red Rising your color could dictate your career and living conditions. Although people want to belong somewhere, they also want to define themselves and set their own boundaries. 
• Getting pit against other groups, sometimes pointlessly. Being separated into categories is often a setup for conflict. And often, it's a conflict that pales in comparison to a more serious battle on the horizon. The House Cup that gleamed so appealingly in the early Harry Potter books fades away later on, as the houses are forced to unite against a common enemy. The inter-district competition of the Hunger Games is a show of power by its organizers, meant to keep the rest of the world too distracted and submissive to rebel. 
• Developing lopsided worldviews. Despite the benefits of spending time with like-minded people, it might not always be in the characters' best interests to do so. Would Slytherins be better members of the wizarding community if they learned something about teamwork from the Hufflepuffs? Would short-tempered Gryffindors benefit from being around some Ravenclaw objectivity? 

This last point makes me wonder if someone like me could be sorted into Gryffindor anyway. If we want to become braver (or improve ourselves in some other way), isn't it refreshing to be around people who can help us find that quality in ourselves, and teach us how to develop it further?