Consider also: I might feel a certain way and not want to let people know; but my face / expression / other nonverbal cues might let people know that's the situ

Consider also: I might feel a certain way and not want to let people know; but my face / expression / other nonverbal cues might let people know that's the situation without giving them further information. How can you convey a feeling of guardedness without declaring it? Declaring it would violate your own feeling of not wanting to declare your feelings. Also, when you've declared something explicitly, you're now tied to it. Emotions are fluid and changing; nobody wants to have to establish some artifact, some fencepost of where they're at and then be tethered to it for the entire conversation.