We perceive by making distinctions. And a fundamental distinction we make is the distinction between male and female - for the very first question we ask when a baby is born is,""What is it? Is is a boy or is it a girl?".
However a more fundamental distinction than gender is the distinction between the inner and the outer.
For instance, sip a clean, fresh glass of water and it is delicious. But spit into the glass of water and sip, and it is disgusting.
And disgust is the sign a taboo has been broken. In this case the taboo is the one against mixing the inner and the outer.
And this is a very fundamental distinction, with its accompaning taboo, across all cultures.
And this distinction and taboo naturally give rise to the idea of inner and outer and indeed the inner and outer in personality. So we arrive at the extroverted personality and the introverted personality.
And you have an extroverted personality and I have an introverted personality. But alas we have not learnt how to create a positive relationship between us.