I think it's even more complex than that. There's only one human I can understand pretty thoroughly, inside and out, and that's me -- and even then, there are a lot of limitations!

We cannot know all the thoughts and experiences of another human being. Even when that person is 100% genuine, there will be aspects to that person that will surprise you!

And that doesn't even get into the weeds of autistics, ADHDers, and intelligent people (I happen to be all three) -- who learn from an early age they have to pretend to be something they aren't, otherwise they'll face intense bullying and ostracision. And even then, there's going to be something "off" about them ....