Because you are allowing yourself to think about him and how much you miss him. If your not thinking about him, you wont miss him. But not excatly, even when your not thinking about someone doesn`t mean you dont miss them. But you possibly you care about him, or your just attached to him.
of course he would miss you, that is, if he really cares about you
missing so badly- you really miss a person dying to see someone- you would do anything to see someone again
he either flirts really badly or becomes mean but says that he is only joking
It is a colloquial phrasing, because you are using "really" to mean "extremely" and "badly" to mean "desperately" or "greatly." A less colloquial form is very badly.
Chances are he will treat you badly so just don't bother with him, move on and find a new guy who doesn't think your annoying.
He probably wants you to tell him that you miss him too.
Bottom line? Why do you want a guy that treats your friends badly? You just said he's a jerk! Don't be surprised when it finally dawns on you that he really is a jerk.
I miss you terribly, would be better.
That you like him, or you're a very jealous person. :)
Justin bieber sings badly
As a guy myself, I would say yes, if he asked you if you miss him.
hang out and talk with him more if he knows whats good for him he won't miss out on this chance