The primary function of your brain and nervous system is simple: to keep you safe and ensure your survival.
In early childhood, your survival depends entirely on your primary caregivers. Your system knows that without their acceptance, your survival could be at risk. That is why it does everything possible to gain acceptance and avoid rejection.
How?
By observing them very carefully.
Imagine that your mother consistently reacts negatively whenever you express what you want. Your system notices that expressing your desires leads to rejection.
Rejection = danger.
To protect you, it begins creating an internal process that gradually stops you from expressing your desires altogether.
This process develops layer by layer, each time your desire is met with a negative response.
The first layer might be confusion.
"Why is my mother upset by what I want?"
You may try to explain yourself or make her understand.
The second layer might be fear and tears after being punished for expressing yourself.
The third layer might be deep sadness that you learn to suppress because you don't want to upset your mother again.
And so the process continues. Layer after layer, an aspect of you develops that no longer wants anything at all.
Eventually, you may even become proud of having no desires.