Girls who are sweet and not hideous get the burden in life of having creepy men make passes at them. I'm guessing they assume that by not screaming and running away, these women must either want bone jumping or are easily manipulated into it.
On behalf of the non-ugly girls who say "hi" back in the hallway: No! NO! Bad greasy man, BAD! (hits on nose with rolled up newspaper). I'm not interested in your guitar playing. I don't want to wake up next to a lava lamp. SHOO!