I am immune to emotion. I have been ever since I can remember. Which is helpful when people appeal to my sympathy. I don't seem to have any. (1.1)
What's John so afraid of? Emotion, for one thing. He can't stand the idea of getting hurt so he puts shields up so people can't hurt him. As much as he likes to think that he's immune to emotion, we know he's not. How else could Marisol hurt him in the end? Besides, hiding from emotion is a kind of emotional thing to do when you think about it.
I was so surprised. "Of course you'll make it. If you can't, nobody can."
"That's what I'm afraid of. That nobody can. Not really." (5.70-71)
At least Marisol's honest. She's scared that she might be forced to keep living the path her parents have laid out for her, whether she wants to or not. Her desire to make it on her own is more important than the relationships in her life, but she's scared of this, too.
I didn't want to hear anymore. All of a sudden I was scared, scared of the feelings she'd had, and I'd never had, and scared of what would happen next. (6.63)
After Marisol's story about Kelly, John feels down. He expected that Marisol got hurt, but nothing could prepare him for how hurt she'd been. He doesn't want people to have that power over him because he's afraid of getting hurt just like his friend did.
"I'm afraid to have another girlfriend—I don't even look for one, because I wouldn't trust her anyway. I spend my time with Birdie and Gio now, but sometimes I'm even afraid with them." (9.53)
Poor Marisol—once bitten, twice shy. She's scared to open herself up again, because with it comes the potential for more pain. Eventually she gets over this fear, though, allowing herself to escape from its clutches.
"So I took all the sadness of the divorce, and all the love I'd once had for both of you, and all the fear I had of being alone, and turned it into a stone wall to hide behind. To protect myself. I'm so protected now, dear Mother, sometimes I feel like I'm barely alive. I am immune to emotion. And I hate you for it." (10.59)
John's letter to his mom shows how scared he is of what can happen to him in life, especially when he's so sheltered. Sure, his parents give him a place to live and food, but he doesn't feel like that actually gets him anywhere. What happens when all that goes away? What does he do then?
I didn't read it right away; I had to calm down first. I was a frigging mess just imagining getting through this whole prom event. In fact, my nerves had been shot ever since I wrote those letters to my parents. Marisol hadn't mentioned that side effect. It was like my skin had all of a sudden been turned nerve-side-out. The letters were hidden under a pile of socks and boxers in a drawer, but I'd have to move them somewhere else or give up changing my under-wear. Every time I opened that drawer a cold wind shook me like some kind of supernatural force. (11.16)
A letter from Marisol has the potential to cause major harm to John, which is why it makes him freak out so much. He's not just scared of having friends—he's also scared of what happens when he's vulnerable with them.
You could hear a couple of canine killers scratching and moaning at nearby doors, hoping for a chance to get free and dismember us, but it didn't scare me nearly as much as thinking Marisol would never say she loved me. Finally she grabbed my arm firmly with both her hands, which, for some reason, hurt almost as much as the slaps across the face. (12.108)
When John finally comes clean with Marisol about his feelings for her, he's scared about what she'll feel… even more scared than getting beat up or bullied. For him, admitting he's not as immune to emotion as he wants to believe he is is frightening.
"Of course I love Al, but sometimes I get a little… afraid." She drew imaginary circles with her finger on her skirt. "You don't think he'd do what your father did, do you?" (14.23)
John's mom is just as scared of getting hurt again as he is, only she's actually able to admit it. Sometimes John seems to want his mom to figure this stuff out by herself. He gets that she's scared of change, but he shouldn't be the one to help his mom through that.
"I liked the poem, Gio."
"You did? You liked it?"
She nodded. "It scared me a little, but that's all right. It was true." She laughed lightly. "How did this happen?" (16.27)
When John reads his poem out loud, everyone cheers for him… everyone except Marisol. She's more scared than excited by what he shares in his poem, and even though they know each very well, Marisol still doesn't know John well enough to anticipate just how scary his thoughts can be.
I'm ready, I think, to join them. Very anxious, more than a little scared, susceptible now to anything that might happen. (17.36)
In the end, John changes to let people in more. Sure, he's still scared about what might happen, but he's willing to at least try to open up now. He knows he might get hurt, but he's not as freaked out anymore.