So basically, on the one hand, hard to get is a Machiavellian psychological tantalization technique to make the guy desire her more than anybody else, while on the other hand, it is a test to see if the guy is actually a little boy rather than a man, in which case the girl WILL blow him off and the guy will whine to everybody about how the girl is such a tease. Meanwhile, a real man will hide from everybody (except maybe his mother -- which is why mothers-in-law oftentimes are hostile to a woman!) how she's affecting him, which will only make her continue her actions. A classic example of "boiling the frog slowly".
The only reason he did not blow her off entirely was the fact that they actually kept progressing... two months later, he had her (real) number; two more months later, they actually went out for the first time; two more months later, they kissed; two more months, they... well, you get the picture. Tim only started to get suspicious six months after people started calling her his girlfriend. Yet Lisa actually treated him so well that he couldn't run away.
Ten years later Tim found himself with four kids and Lisa making dinner for him every evening. Lisa smirked as she gave him his favorite lasagna. Mission accomplished!
Mike: So I tried letting Sarah know that I was interested in her, but she didn't seem to care so I gave up and hooked up with Jessica instead.
Perhaps the most evil aspect of this technique is that if the guy loses it and turns needy or complains to her, she blows him off and looks for somebody else, thereby making it seem like she has been a tease all along.
Sexyface: *replies* Hell No.
Thabo: *thinking* She's just playing hard-to-get.
Hey Alyssa your my bestfriend.
Courtney your a slut.
Wanna go out with me Courtney?