Wait, what? I certainly don't have one. Most of us (not all! neurotypical experience isn't universal) have a skill trained since childhood to guess at the emotions of others based on various visual and behavioral cues, but we also know that these visible cues can be faked by (for example) a skilled actor, as the "sensor" has zero insight to the actual emotional experience.

If I make the assumption that someone else (e.g. you) function the same as I do, then I can reason that "your behavior X implies your emotional experience Y, because it does for me"; however, if we can't make that assumption, or (as is the case for non-human minds) we know that the process is substantially different - then there is literally zero basis for any trustworthy reasoning whatsoever about that internal emotional state.

I just typed a colon and a parenthesis. Your brain interpreted it as a smile on a human face.

You are equally mistaken in the use of your emotional sensor. Our brain fills in a LOT of gaps based on OUR training.