How can I tell if a girl is creeped out? What's a way for me to avoid it?

Anonymous
I have no idea what I did. I just go up to people and say hi to them. A couple of girls just look at me like I came from Mars and they act all creeped out when I said hi to them.

So how would I know if a girl is creeped out? How can I avoid it? Is it my fault? was it their fault for being shallow?
How can I tell if a girl is creeped out? What's a way for me to avoid it?
3 Opinion