“It doesn’t always start as an argument. My eldest (9) son will just calmly ask me why he can’t play Call of Duty. I respond in kind, explaining that it’s an 18-rated title, and that he’s nine years old. I assume that my logical perspective will destroy his tiny mind. But all his friends play it, and have done for ages, he tells me. I can check this, because he plays on my gamertag, which is now littered with bizarre usernames only children and clan-members could come up with.”