How about feelings?
Whenever I talk to people outside the school system about my students on the spectrum, I get questions like: Can they have feelings like us?
Of course, they do! They cannot always put a name on it , control it or understand how and why other people feel differently but yes, they have feelings.
With people they know and trust, the smile and happiness are there. When you take away something they like, there can be frustration and rage. When facing a new situation or challenge, you can see fear and doubts.
On the other hand, they will not always understand why you can be upset with something done that they see fit. They may not laugh at the same jokes or situation as you. They may not find beautiful or ugly what is considered as such by society.
I can assure you that when they cry, it is sincere and heartfelt, their frustration is easily seen. But when they are smiling , it is contagious.