There is a moment in parenthood when your child discovers you are not infallible, that you can be beaten. The first time a kid wins a game of tennis against their mum or dad, or solves a maths problem their parents can't even begin to understand, it is profoundly bittersweet. While it is wonderful to see your child growing up and becoming independent, when they get good at things, they are a little bit less yours, and you are a little bit less heroic. It is sometimes hard to be the grownup in that situation and not deal with it childishly. I discovered this on Saturday when my eldest son and I were playing Apex Legends.