Dr Jekyll and Mr Hyde.
There are many whom we would call nice people - kids and grown ups.
We just don´t know what is going on behind closed doors or deep in the mind of a person.
You might have the nicest and most helpful co-worker, but he beats his wife.
Your impression is a nice guy. He probably would be seen as a nice guy to work with.
Then you have a man who might be very strange and you might avoid him, but he is the kindest person you can imagen.
The same Dr Jekyll and Mr Hyde will happen with women/boys/girls.
One side is very nice - as a rule the dominating side - the other one is not as nice and can be by some people real cruel.
We are not naiv just because we don´t have all the facts. I think we are more torn between the terrible facts and the good side.