As toddlers, we all had a moment of realisation:
What we know is not what other people know.
What we think is not what other people think.
We have an inner world.
That is different from their inner world.
This enables us to tell our first clumsy lies. It is also when we first learn that the world is separate from us.
We then apply this clumsy lying to ourselves: We want to believe that we can control the world. That tantrums will bend the world to our wants.
The older we get the more skilled we get at lying. Believing that we stopped throwing tantrums. Believing that we have stopped trying to control the world.
The path to more honest interactions is letting our knowledge of what we cannot control, become bigger and bigger and bigger.