Why do girls look down or away when I try and make eye contact?

Anonymous
This specifically relates to when I am walking by someone coming the opposite direction. Somebody that I do not know!

I could venture to guess two main reasons why a girl would not make eye contact with me. First, I am not cute enough for them to want to make eye contact. Second, they are too shy to look into someone eyes. Third, maybe they didn't see me.

The reason I do not think it is the third one, is because a girl will SPECIFICALLY look down, away, or at a cell phone right when I try and initiate eye contact.

I can tell you that I am not ugly, I am a decently attractive guy. I have dated and been in relationships with beautiful woman. So I am not sure why a girl that does not know me at all would go through great lengths to not make eye contact.

but..i could be wrong. ;-)

Any thoughts?
Updates
+1 y
I read some of the answers, and it leads me to a second question.

Are ladies more surprised if a guy gives them strong eye contact. Thus not being ready for it pushes it along to likely have a shy look away or look down?
Why do girls look down or away when I try and make eye contact?
12 Opinion