Why do girls play around with guys feelings?
Well, most girls do it to get a confirmation that they are good/hot/accepted etc. enough amongst guys in order to boost their ego. Which is kind of sad, really.
Or, they just love the idea of getting chased by some guy.
I've had several girls trying to get me to chase after them, which have only resulted in me telling them that I'm not going to chase them because they're not worth my time anymore.
Afterwards I just ignore them and move on.
Most of them have flirted like crazy with me, and every time I've thought they have been just the "flirty type" but not really, some of them have even kissed me.
All I can say is, if a girl have given you a lot of compliments/flirting/kisses and then suddenly out of the blue just drops it, that usually means that she's trying to get you to chase her.
Or, possibly, she's clueless about her feelings.