Difficult To Tell

Some people are the quiet type, they usually
have nothing saying or to ask. They just love to listen.
They normally like to smile or laugh at any little joke.
It's difficult to tell what they are truly thinking about since
asking them why they are smiling out of the blue will just result
in them answering, "nothing". They only find the need to explain
when caught on the spot or else they see it unnecessary to do so.
Even with catching them on the spot you would have to be smart
else they would find their way out without saying anything substantial
you can hold against them. But if they feel safe with you, they try to
open up once in a while. It's difficult to tell without them choosing to
tell you. Get used to it.