Most how naive he is I suppose. The video of his sister blowing what's his name, Taylor I believe, and he goes "man, looks kinda familiar, but no way would my sister be doing that" but the only thing you can't see is her eyes. It's clear it's his sister. And he chooses to wack off to it. Dude is just super stupid. A few other things he does made me dislike him a little bit more at a time. He doesn't seem to be a bad kid, but really it's not like we have any incentive to like him from the beginning in the first place as there is no buildup to anything.
