I think it is good when people, especially T's, are open to the possibility that they can't "read" people's expressions. I think there is some research on how bad people are about reading emotions, with disgust being the easiest of all of them to read. I think it is better for someone to ask you what you feel than to assume they know it from your expression.

I know for myself, that I being abused as a child and hiding it from the adults in my life, has made me difficult to read. People who were shamed or punished for their emotions as a child also learn to hide them and this follows them into adulthood. There are probably other reasons why people may not always show what they feel, but I think it is positive when people don't just assume they know because in my experience, they are often wrong.