. Nothing in my opinion. . I like (and prefer) athletically slim women, but the collar bones would probably be rock bottom last on my list of sexy parts. . I doubt that I would even be consciously aware of any protrusion unless it was so obvious that it started to repulse me. .
I love them. and i agree that it makes girls look more elegant. also it probably makes girls appear skinnier. but deffinatly elegant. i sometimes use makeup to highlight mine even though you can see them already
I know that on my boyfriend, I find it makes him look more muscular and somehow more manly haha.
I think it's just because collarbones can make a girl look very elegant.