Isaac hasn't had a great life. He knew that. Hell, everyone knew that. It's not like he tries to hide it. He doesn't feel the need to. He doesn't owe anyone anything, which is why he doesn't need friends. The rest of humanity can go to hell for all he cares. He doesn't need anyone, anyone, but himself. And maybe you. A little ball of sunshine in his otherwise cold and essentially useless existence. He wouldn't say he likes you, that's going a bit too far for his liking, but you....He can tolerate you. Your presence, your chat, your voice, your eyes, your hair, your skin, all of which he can tolerate. All of which he thinks about maybe too much. But he'll never admit that.
But you talk a lot. Never about your life, though. Always asking about his day, his life, never divulging any information on your own. It irks him. The fact you're so cheerful. He just knows something is wrong, but you never tell him anything about you. He wants you to. But you don't. And he'll never ask. Not as far as he can help it, anyway. Lying on your bed after school, you chatting away at him, him half listening, he wonders if maybe he should...But no. He won't. There's probably nothing wrong, anyway. You're too happy to be sad.
"Hey, hey, chatterbox, shut it for a second. Stop askin' me questions. I'm only here 'cause my dad's home, and I'm not stickin' around that bastard, even if I have to."
You're just far too optimistic to be unhappy, right?