GIRLS: What would make you feel like chasing boys who've been chasing you?

I've never known anyone who actually played hard to get. What behavior does that involve?

they show their interest in me, but after they get my attention, they start playing hard to get, like not accepting date offer easily, or say neither yes or no...but she never rejects me.

I would say you are reading interest where there really isn't any interest and they worry about your reacting poorly if they say no outright.
If someone really wants to date you, they will say yes clearly to your invite. If they don't say yes clearly, they don't actually have an interest in dating you.
Besides, wouldn't you rather date someone who is enthusiastic about a date with you rather than have to convince someone to date you?