Here is my personal experience--take it for what its worth. Shortly after I begin dating a woman, I find out that she and her friends thought I was "cocky" before they even knew me all that well. They based their opinions on my attitude, comportment, posture, etc., which she likes. Then, when she finds out that I am really the dreaded "nice guy", which she hates, she begins to think she can use me as a door mat. I then make it clear that I could not care less about walking away at the first sign of her bullshit, which she likes. She then reverses her untoward behavior until she thinks it is OK again to tread on me, which she hates. And on it goes.
That scenario has repeated itself with me for the last 20 years and is one of the few things in life that I can count on to be consistent. All women claim to want a "nice guy", but they don't what to do with him once they have him. I agree completely with supernav--they mostly want someone to bitch to their friends about.