I am an HSP too! I definitely give off an unapproachable vibe, not on purpose but maybe more of a subconscious defense mechanism. All of my coworkers and classmates comment frequently on what a private person I am. I think that I have more intense feelings about things than most people do and others can't relate/probably get weirded out when I express that in conversation about casual small talk type subjects that shouldn't really involve much emotion