Our psyche is composed of 90% subconscious and less then 10% conscious. I believe that the very moment you see a person you immediately figure out who they are. You have already known about them everything. This is how subconscious works. And then you have 2 options: 1) you trust yourself, you are sure that you understand it right and start to reveal this knowledge through interaction with person, to make it aware. But in general you never change your opinion and attitude about them because you knew all about them from the beginning.
2) you think intuition and all stuff is bullshit and begin to persuade yourself that no, he is not a jerk he just had a bad day. Or: we have to date for five years before having sex because we have to get to know each other better. And then after 20 year living under the same roof you discover out off the blue that you live with a stranger without anything in common in your pocket.
Remember how many times you met a person, didn`t like them for no good reason, convinced yourself that it`s your bad and then they turned assholes?
My beloved Carl Gustav Jung tells a lot about collective Unconscious and the way ideas walk around.
Plus my own experience
The moment I see a person I`ve already known whether I love them or hate them, should I open myself or hold back. For me there is no sense to live a half life.