I had an email from a reader of the first edition of this book, who pointed out that an example I gave in one of the Rules in this book was in breach of another Rule. Nope, I’m not going to tell you which one. You’ll have to work it out for yourself like he did.

In my defence, I’d like to point out that this means I was following the Rule about not being perfect. However, there’s no denying that the reader in question had me bang to rights and, as he observed (very politely I must say), it’s important to be consistent.

Well, I’ve never been arrogant (or stupid) enough to claim that I never break any of the Rules. After all, they’re Rules that I know work from observing other people, not a list of personal preferences. So I try to follow them as closely as I can, and the older I get the more often I get it right. But that’s not the same as always.

However, we certainly should aim to be consistent about following whatever Rules we decide to live by (the ones in this book and/or any others). There’s no point in choosing a path if you’re just going to wander off it at whim.

I find that my children are a big help here.^* (If you don’t have kids you’ll have to work that bit harder to identify your own inconsistencies.) If you’re debating a point of disagreement with the children (yes, that is indeed a euphemism) you can rely on them to draw your attention to any inconsistencies in your line of argument, or indeed any inconsistencies between what you’re telling them now and what you yourself did yesterday. It’s a fine line between inconsistency and hypocrisy, and the clearer we are about what we believe and why, the easier it is to be consistent in what we think, say and do.

For example, suppose your child points out that you criticize them if they bitch about classmates behind their backs, but you were having a moan about a colleague on the phone to your mum last night. You may need to think about the difference between bitching and having a much-needed moan, and then make sure you’re consistent – with yourself as well as your child – about what you allow.

And here’s another thing. It makes life easier for everybody else if you are consistent. Erratic people are difficult to live with and be around. So are moody people. If your friends and family don’t know how you’ll react to the same event or suggestion from one day to the next, you make them live their lives on edge. Unless you are a hermit. I’m not talking about being predictable and boring. Your ideas and activities and enthusiasms can be wonderfully unpredictable and fascinating. It’s just your behaviour towards other people that needs to be reliable and consistent. You have the potential to make people’s lives richer and easier and better – or darker and trickier and more exhausting. Which do you choose?