Ah yes, I forgot to say something about this. The thing that made me most mad, though, was this part:
Axel: Xion is like a mirror that reflects you.
Roxas: Wat
I mean, really, Axel. Xion absorbed what little brain power Sora had, leaving Roxas with pretty much nothing but Sora's anger, impulsiveness, and overly dramatized loyalty. Now is not the time to be using fancy metaphors on the poor boy. You could have just come out and said "She's a replica. The stronger she gets, the weaker you get." And then he has the nerve to be frustrated when Roxas doesn't understand...
Xion...was a little silly, but I sort of understand. She was ashamed of what she might be, and so couldn't tell her closest friends friends about it. It's like talking to a therapist or going to twitter instead of talking to actual people. I also never understood Roxas getting mad at Axel for attacking Xion, and never once wondering or asking why Xion raised her keyblade at him. And then Xion just says, "if he hadn't attacked me, I probably wouldn't have come back." Like what. This doesn't even make any sense. Come back if you're going to come back, leave if you're going to leave. And of course, Axel had to keep all of his secrets because of his plans with Saix... I also feel like it was hinted somehow, somewhere that Roxas sort of puts Xion onto this pedestal of perfection because she's a reflection of how Sora sees Kairi. Roxas kind of has every right to be mad at Axel, seeing as its made obvious in the end that Axel knows pretty much everything about Roxas and Xion and never spills. At least, at the end; everytime before that was just Roxas being impulsive. Character flaws... but without character flaws, there would be no story, and nothing would really happen.
You also have to take into consideration that Roxas and Xion are completely new beings that don't really know how to function with emotions; supposedly, they're not even supposed to have emotions. Roxas understands things least of all, and both Axel and Xion sort of let him exist in his own little oblivious bubble, not troubling him with their problems.
Also, Roxas and Xion are technically 14-15 years old, if you don't count them as being 0-1. Name a 14 year old girl who acts rational all the time and we'll talk. lol.