I mean, for real, he spends half the book sulking about how he is being trained to be the most powerful enchanter in the world when he'd rather be back at his posh boarding school playing cricket with all his rich friends.

To be fair, he was stuck in a situation where he had nobody even remotely close to his age to talk to. I'd sulk too if I were 11 and couldn't spend time with other kids. (Well, I wouldn't, but most people who had more friends and were less introverted would.)