Well, there could be a couple reasons...
Maybe he wants a "badass" type of girl? Naw...
Hmm... if you don't say anything, I could predict that he'll force words out of you.
Although it seems he wants to help you... although, perhaps... it could be because you ask him so many questions, it strips him of his free time? I mean, I, as a guy, would be slightly annoyed if I were constantly asked questions... (I won't be like the above described, but...)
Maybe it was a bother?
Next time... talk to him. If you like him to the extent that you'll accept him the way he is, no matter what the case, the everything... let him know that you'll accept him the way he is. He'll probably realize something. He may not realize it at the instant moment, but... it's worth a shot.