Why do I worry so much about putting myself in a box and labeling myself?

That's only understandable - labels seem to make everything understandable and easy, even if they don't tell half the truth and often actually make it impossible to see all of it. Still, they are comfortable, and they make it easy to describe yourself to others, even if there will always be parts that don't fit.

Probably because we've been taught that everything and everyone needs to fit in a category. It's all about social convention. But conventions are not really concerned with people's happiness. If what makes you happy and comfortable, what truly feels like you, consists in not labelling yourself, you're free to just live your life and be yourself without labelling your feelings and identity.

Sometimes we can find ourselves with fragmented feelings of identity. As someone living with BPD who tends to have a very strong sense of "fractured identity" it’s common to drift from box-to-box trying to find things that we can relate to fill out any loneliness or confusion we have. For many people, labels don't work for them because they have a certain sense of personal identity that doesn't require a predetermined title or label (they may be very independent or secure in not having a designation). You may worry about placing yourself in a box because you do not want one factor to completely define you or that you will be restricted labelling yourself into one category. You have many other attributes and you want those attributes to be recognized or it may be the case that you worry about being stigmatized by attaching yourself to a label (e.g. it maybe identifying as someone who lives with depression, or identifying as LGBTQ+ orientation). However, some folks have feelings and emotions intertwined with their identity where they may seek validation or communities that they can belong to (e.g. shared experiences, personalities, hobbies). In this way putting themselves into a box gives them a support system and a chance to reach out to those going through the same experience as them. The feeling of wanting to belong is more-or-less universal in some ways. We are social creatures who want to belong to a community with shared values. Having a label can be very freeing and validating for those who feel they need more reassurance and want to know the “why’s” of who they are.