Friendometer.

Figure A: Categorization of how the susan acts (nonintentionally) amongst different people depending on their degree of closeness to her -- study conducted by yours truly. The voice that attracts the geeky middle-aged men (ref: PhoneService post) is the 0% friend voice which is the most pleasing to the ear for all to behear and is only offered to strangers for the reason that it takes the most energy to produce. The lucky(?) 100% friends are presented with a low growly voice mixed in with copious--nay, profuse!-- amounts of man-repelling, deafness-inducing, maj-explosive laughter!