Quote Originally Posted by Kraco
Indeed, but I'm not watching anime for absolute realism. If I wanted that, I would look out of my window. That's why I said I hate main characters like that - I want them to do better than many people would likely do in the real world. Besides, I haven't got the bloodiest idea why Jin is so fixated on whether Nagi is a god or not. It looked at some point like he was happy enough with her, despite all her antics and the difficult personality, but then he began to ponder whether she's really a god or not... Who the hell gives a shit? He could think about it, but it certainly shouldn't change anything or make him drive her out of the house.
Again for some reason they choose the "reality route" where people are never satisfied with what they have and can loose happiness and everything for the sake of searching for an answer.

In Jin's case, things are a little different though, at first he was only annoyed and got over it, even thinking his life was nice with Nagi around.
The turn was when he remarked his body gets wonded worser and worser and he started to fear for himself. Maybe he doesn't want to end like the kittens. Even if he doesn't think like that, he still wants to understand clearly what/who Nagi is, so that he doesn't end up loosing his life, sanity, lifeforce or whatever.
Zange-chan kung-fu ultra-violent moves is also part of the questionning, as she can be very different from the very nice little idol she shows most of the time.
Nagi also has different faces.
Jin needs to know what may come next, so that he can prepare or just put distance beetween himself and Nagi, which already happens.