Why does he do this to my head?

He might not want to reply to those kinda messages because he wants you to be like "hey cutie, what's up" too. he is only being so flirty because he wants you too know he likes you but he wants you too like him too. so he thinks that if he doesn't reply to those kinda messages you will get mad so then you will start saying the same. That's the way all the guys are so don't worry, just start trying to flirt back if you are interested, if not then just ask him why he won't return your text messages.

personal experience! well sorta
the guy I like sometimes texts me, and I don't answer
this is for either of two reasons
1. I want to be kinda mysterious, so he thinks, what could she be doing where she couldn't be answering my texts?
2. he either doesn't have texting or he has limited texting
these are the two reasons I don't text him back sometimes