I'd chose invisibility. I love to people watch and being invisible would allow me to do that even more - they couldn't catch me looking at them if that makes sense.
The ability to tell what people are thinking. Not what they say out loud but the voice in there head. So when someone says, "I love your new haircut!" But the voice in their head says, "oh my gosh! What were they thinking!!!???" I'll know maybe it's back to the hair salon I go. Silly I know but I would be interesting