In a vacuum, without the influence of other functions, they're all scary. A sensing function, with no thinking, no feeling, no intuition, is just someone running around experiencing and experiencing any exciting thing they can, like a living, totally unfeeling bundle of chaos. Mass murder? Eh, could be fun, may as well try. Feeling without regulation of thought is extreme reactionary, dangerous in its wildly over the top response (though in some cases they could be more suicidal than violent). Pure, unregulated thought may tend towards near total isolation or disregard for people, until it looks into finding out about something that requires endangering, killing, torturing or otherwise experimenting on people. Intuition by itself, well, I dunno. Without F, cold plots and plans? no S, assumed meanings and paranoia? Without T, wild and schizophrenic ideas that case them to lash out madly?