There are a lot of reasons...
Your sense of identity begins the moment you are born. The moment you come into the world you realize the relationship and differences between yourself and your mother. A sudden shock of knowing that you are separate beings. These are the first moments when your identity is created. Furthermore, self-identity and self-esteem begin to be formed.
Again you might ask, why is identity so important to a person?
Well, identity and self-esteem are closely wrapped in one another. A strong sense of self leads to good mental health. The ability to describe your self-identity in a way that is clear and meaningful gives you a foundation on which to interact with the world around you.
Of course, this leads to a healthy connection between self-identity and self-esteem.
In some cases, your strong sense of self might be based upon what other people think of you, while in other cases you might describe your self-identity based on your own internal thoughts and ideas.
Regardless of where your strong sense of self comes from - the moments we normally feel hurt or upset are when other people see us differently. That is one of the reasons why identity is so important because if it's not in harmony with the world around us we might feel misunderstood - almost like we're battling to feel appreciated for who we are.
Here's the thing...
No matter what way you create your identity or how you define your identity, most of us will suffer to a certain extent from how society wants us to behave and act. A few boxed in categories come into mind that I think we can all relate to - child, mother, girl, boy, short, tall, smart, stupid, hyperactive, and the list can go on.
Why is identity so important is a question that has been asked for decades.
Why is Identity Important? Ask Maslow
Abraham Maslow was a Psychologist who is best known for his work on defining our hierarchy of needs, specifically that when lower-level needs are not met then we do not have a chance to move onto the higher-level ones.
In his chart, physiological needs are at the lowest level and self-actualization is at the highest level.
The reason I point this out is because identify isn't something that we have time to think about much if we are searching for food, water, and shelter. Only until we create friendships, create respect, and build self-esteem can we fully self-actualize.
This allows us to become the best versions of ourselves, whatever version that might be.
So next time you think to yourself - why is identity important? You'll have a good foundation to start from.