Let's say you approach a girl at a bar or club, you deliver your opener and you say a few things and then she rejects you. And when you think that this pickup is over, she watches you all the time from a distance.
You catch her staring at you for some time after you left her. Or maybe she tries to be near you, either stand by you or dance near you. Why is that?
First, let's say that if she's acting like that, then she never rejected you. It was an autopilot response. Think to the last time you walked down the street, and a vagrant asked you for change. Perhaps you said "no", and kept walking. It was just an autopilot response to a social situation. Girls are the same. Their logical social conditioning kicks in and says "This guy is trying to sleep with me. He may be attractive, but who cares, I'm not meeting a guy at a club."
Notice also, how in all of the times that you've told a vagrant "no" when you were asked for spare change, there were those few times when someone asked you for help, and you said "no" out of habit, when in fact as you walked off you might have thought to yourself that you could help this guy.
The same goes for girls. They'll screen guys out as an auto-pilot response, and later wonder if they made a mistake (but they don't care, because another guy will come along in two seconds anyway).
Attraction and how alpha or how sexual you are is not a factor here. Even very attractive guys get rejected for no logical reason. This is purely an autopilot response that you have to recognize and dodge.
As I mentioned, girls will reject a guy as an autopilot response. They think "I don't know this guy. This guy knows what he's doing, and probably does it to all the girls. I'm not this type of girl."
Girls are used to sex going down in a certain way. Walking up to girls and overtly trying to pick them up goes against what they're used to. It's a violation of social norms. Girls will tolerate it as cute, and they'll be interested to see what you'll do. But they'll rarely sleep with you (unless they are at a certain point in their lives where they are open to the idea, which I'll post about it in future posts).
Another reason to that is when a girl wants to see if you can handle the rejection or if you behave like a beta male for the rest of the night. Or even she may want to see if you are really like her or you just want to have sex on that night. You never know for sure.
If you see this behavior, then is time to go and talk with her again. You can start the conversation by saying something funny, like "deja vu", or anything else. It doesn't really matters, because the girl is into you already.