There is authentic and then there is also plain rude. I believe myself to be an authentic individual but I would never tell someone something they obviously didn't want to know. I don't think its my job to give everyone I know or meet the dose of cold reality they don't want to see. I would hate to be the guy that blasts the hopeful college student into a mickyDs job because I told him I don't think he is smart enough to make it through, truth or not.
If they want the truth and ask for the truth I will tell them the truth. There is a common sense element here. I would never tell my wife she is gaining weight, nor would I tell my mother she annoys me when she calls to complain about stuff. IT WILL HURT THEIR FEELINGS, they are southern and proper and above all courteous.
I might work it a little more with people I could care less about, but there really aren't that many people on the planet I could care less about.