Sharing a room with a younger sibling means someone’s watching how you act when you think it doesn’t count.

Somebody younger in the same room sees the unedited version: how you speak when you are tired, what you do when you think it does not count, how you behave about being wrong. They are not judging it, they are learning from it, which is the heavier of the two. Most of what gets passed down happens in those unguarded minutes rather than in anything you say deliberately.

Choose one thing you would want them to copy and do that on purpose this week, including on the days you do not feel like it. Apologise out loud when you get something wrong.