OP, I am Ravenclaw to the core. In my private life, I am the complete opposite of warm and fuzzy, and most people who know me had me pegged as a future lawyer or police officer (while moonlighting as a meter maid or at the DMV for some sadistic fun on the weekends). I chose nursing because it's interesting, and I have always enjoyed rubbernecking the strange, gruesome and unique.
It turned out to be a perfect fit. I learn to exude warmth when interacting with patients and families, because that's what is needed to get the job done. I love interesting and weird things, so I always want the difficult, gross or oddball assignments. I take immense pride in dealing with things no one else wants to be bothered with, if only for a personal sense of accomplishment. If a patient's family is annoying as hell, I want to conquer them by making them absolutely adore me, because I am a jerk who wants to be "the best" at whatever it is I'm doing.
Also, being sickeningly sweet is overrated. People take comfort in confidence and competency, IMO. If you are self-assured, calm and in control, patients trust you and believe they are safe in your care. Do it with a smile, and they'll love you, even if you aren't mother earth incarnate.