Going through the positions in a relationship hierarchy, there are so many that just aren't favorable.  And let's be honest, most women that you're dealing with, fellas, want to be the only one, the main chic, the girlfriend, the wifey, and sometimes ultimately the wife.  No woman truly wants to be a member of the harem, the jump-off, or the other woman forever.  Some don't even want to be just the friend either.  So in order to advance in the system, they'll do what I call the power move.

The power move will be some gesture or gestures that are not congruent with their current position.  They'll start to go a little bit farther, show you a little more attention, give you a few more things, treat you better and better each time you see them.  They'll be more understanding than usual, more courteous of your time and feelings. They'll do things for you that will be surprising considering how you've treated her. It'll be those things that will make you stop and say "Wow, that was nice of her"  or "That's odd, why would she do that when she knows I don't see her like that" or my favorite "I never gave her any idea that this was anything more than it was.  Why would she do that?"  

You may think that it's odd or strange for her to all of a sudden start giving you stuff or doing stuff for you.  But what she's really trying to do is separate herself from the harem.  She wants to show you what a relationship could be like if you were to spend more time with her.  Give you reasons why she's the best pick out of your starting line up.  So when you do actually start to think about settling down and deciding which situation you'd like to take a crack at, she has more things tipping the scale in her favor.

After a few weeks or months (or sometimes even years) of this extra attention, if you don't start giving the extra attention back to her, in whatever manner she's expecting, she'll realize it's not working.  She may even realize that there could potentially be another girl in your harem doing more.  So she steps up her game.  Does even more. Sometimes taking the attention to a point where she almost begins to look foolish. And if all her extra efforts still yield no return, that's when you'll see the flip out.  

When she flips out it's pretty much over. She'll truly start 'tripping'. Crying, making ultimatums, carrying on about all the things she does for you and how you just don't care.  Totally melting down into a complete mess.  Meanwhile you're sitting there with that dumb look on your face.  Confused as hell as to where all of this is coming from. Once it hits this point, if you have game and you want to keep her around, you'll probably be able to wheel her back in. She's already invested too much time and effort into you to leave now. Do that slick talk you do, calm her down and things will go back to normal (for a while).  If you don't have any game.  It's a wrap.  She's gone.  Nothing you can do about it. If you don't want her around, great, you've managed to make her give you an out.  You now no longer have to figure out how to break it off.

Don't get it twisted guys.  It may seem strange and unprovoked, but that bird in your flock knows exactly what's she's doing.