I had originally heard about the concept of push and pull, but I simply thought that it meant to do things such as not call her for a couple of days, show disinterest in a conversation, play hard to get and so on. I tried executing this to the best of my ability, but that elusive number was still out of my reach. No matter how much rapport I could build, or how much flirting and attraction I could do, that number was never within reach.
Breaking rapport, is important because too much rapport can be a bad thing. If you go through an entire conversation, it's entertaining, amazing, and you feel really successful, it will mean jack squat because you are ending the conversation on a low note. You burned yourself out, she's gotten her fill, and she does not feel a lingering need to chase after you. That is EXACTLY what happened to me a few weekends ago at the college dance. Very successful conversation, but I ended it on a low instead of a high. I let the conversation run it's course without killing it when it was at the top.
If you deliberately break the conversation at a high point, not only are you leaving her on a good note, but it increases your chances for a Number Close. You prove that she is not the center of your focus, and that you are a man who is limited in his time. The fact that you broke conversation at a point where she feels like she was starting to get to know you will make her even more curious and want to figure out more about you. Even though you will break conversation with her, this also allows you to successfully swing back around to her if you feel like it. Because you ended the conversation on a high note, her reaction to you will be way different than if you completed a conversation with her and then decided to chat with her again.