This Rule follows on from the last, and might help if the last Rule seemed depressingly unhopeful. While it’s true that people can’t change their character, they can – sometimes – change their behaviour.

It won’t help if you think this is a cure-all, because it isn’t. There are times when we just aren’t able to adapt, especially when we’re being asked to adapt in a way that runs counter to our underlying character. So don’t read this Rule and think, ‘Well that’s OK then. My overcritical sister can behave differently, and stop voicing her criticism.’ In theory she could, but she might struggle. For whatever reason (her past, her genes), she believes it’s the right thing to do. She might think it’s just being honest, or that it’s for your own good – in which case why would she stop? The really important thing here, however, is that even if she did stop verbalising her criticism, she’d still be thinking it. That’s the bit you have no chance of changing.

Sometimes, getting someone to change their behaviour is enough. You might not care about their underlying character. If you can get your boss to delegate, that’s the battle won. Who cares how they feel about it underneath? Not you, anyway. But don’t be surprised when a really important project comes along and they go back to their old ways, because they didn’t change deep down, and their old fear of delegating was still lurking beneath and is right back when the stakes are high.

Suppose your partner is infuriatingly messy. You can never find anything in the kitchen because nothing gets put away in the same place twice. You might be able to persuade them that there would be fewer arguments if they behaved tidily, even if it’s not really them. They might struggle, and it might be harder for them if they’re in a hurry, or stressed, or cooking something complicated. But it could work.

You might have spotted the silver lining in all of this. The people around you are a product of their experiences, and when they change their behaviour, they’ll have new experiences to match. Your partner will find out what it’s like to cook in a tidy, organised kitchen. Your boss will learn how it feels to be able to offload some of their work. This might, over time, have an effect on their character. It might help them to appreciate order, or to loosen up. These are things that may have seemed scary in the past but they’re now learning that it’s OK, and even beneficial.

Obviously they might not. If anything happens to reinforce your boss’s old fear of delegating, they may get worse and not better. Similarly, your partner might re-encounter those old feelings of being constrained and strictured which they always kicked against. You can’t assume that a change of behaviour will lead to a change of character. But if it doesn’t, nothing else you can do will. (Although maybe you could try to change your behaviour and become more tolerant?)