Need an opinion!!

ok. obviously desperation has led me here. i'm a pretty attractive guy, or so i've been told, but i get almost zero attention from girls. and i know how girls can tend to be....that is, playing nonchalant and uninterested, waiting for the guy to approach first. i get that; but i've also witnessed the lengths girls will go to when they're interested in a guy. my situation, though, is that girls actually seem to avoid me. if i happen to be walking past a beautiful woman, i notice very often that they seem to avoid any kind of eye contact and pass by as if i wasn't even there (or actually, as if they knew full-well that i was there but pretending as though they didn't and hurrying past). One of my jobs is at a gym, and i notice that certain members (that i see everyday) are friendly and talkative with my co-workers but walk past me as if i'm not there. i don't even get an appropriate moment of eye contact to say 'hey'. so my question is: what could it be about me, if it's not my appearance, that makes otherwise friendly and sociable women basically ignore me?? opinions?? many of these women i'm completely not interested in at all, could care less, but i notice their behavior. I can't understand.