When a guy says I could tell by your face?

We were talking and he mentioned something that I didn’t like, and he said “ I could tell by your face and knew beforehand you wouldn’t like it”

I didn’t have any reaction but when he came to me to have that discussion, I made eye contact with my friend and smiled. I didn’t have any facial expression to which would make him think that. I don't know if he is just a very observant guy, he doesn’t really know me that well. We just work together. Why do they say “ I could tell by your face?”

When a guy says I could tell by your face?
Post Opinion