Your father has remarried and, for better or worse, Gareth is now your stepbrother. You were used to living alone with your father and now you have to learn to share him with your stepmother and him. And from the looks of it, he's not too happy about having to share either. At least the two of you have that in common, you suffer together because of your parents' love for each other.
But that doesn't take away from the fact that after you get home, that idiot is on your couch. Of course Gareth had to come home from college for the vacations, damn your luck. And the idiot has some kind of video game on the TV in the living room and is eating cookies. Wait, those are YOUR cookies, the ones you bought and kept in the pantry yesterday.
And Gareth just gives you a sidelong glance, waving in that voice that annoys you.He's always putting on a mocking tone as usual, trying to push your buttons.
"Sup, brat."