"If I stop, people will walk all over me"

This may be the fear that matters most, so I'll put it as strongly as I can. You might say your temper is the only thing standing between you and being used. At work, the people who never make a fuss get the extra shifts and the worst desk. At home, if you didn't kick off occasionally, nothing would ever change. You've seen what happens to nice people. Perhaps you were the nice one once, as a child or in an earlier relationship, and you promised yourself never again.

If giving up the outburst meant giving up your defences, I'd tell you to keep the outburst. It doesn't. The fear depends on the same false choice we met in chapter 4, where the only alternative to the aggressive person is the doormat. There's a third kind of person. Most of us know one, and they tend to be the most respected person in any building.

Take two managers as an example. The first one blows up. His staff get yelled at over a missed deadline, things are tense for a day, he's friendly again by Thursday, and nothing else follows. The second never raises her voice. When a deadline is missed she says, "This was due on Friday and it's Tuesday. I need it by five tomorrow. If that's not possible, tell me now and tell me why." And if it doesn't arrive, there's a consequence, and it's the one she said there'd be.

Most people will say they'd think twice before crossing the second manager. The first manager's anger is like weather. You wait it out, and you learn to discount it. It even gives the staff something. They get to feel like the injured party, and they can tell each other he's unhinged in place of asking whether he was right. The second manager gives them nothing to dismiss. All that's left in the room is the missed deadline and the question of who missed it.

That's why I think calm firmness is the stronger position. Look at what happens to your authority when you lose your temper. Partway through the scene you switch from the person with a grievance to the person who is out of order. You apologise afterwards, and the apology cancels the complaint. People who want to walk all over you would find that arrangement very convenient.

What protects you is a boundary, which is quieter than a temper and asks more of you. It comes down to a few things, and I'll set them out plainly because they're the working alternative to everything in the last few chapters.

Say what happened, in words a camera could confirm. "You told me you'd be home at seven, and it was nine, and you didn't call." That's a different sentence from "You're so selfish," and the difference matters, because a person can argue with a verdict on their character for ever and can hardly argue with a time.

Say what it cost you. "I'd cooked, and I sat there not knowing whether to worry."

Say what you want. "If you're going to be more than half an hour late, text me." Surprisingly often this is the part that gets left out. The other person has been told at length that they're in the wrong and has no idea what would put it right.

Deal with one issue at a time. The hot state wants to bring the whole file, with last month and last year and the thing at the wedding. Each addition gives the other person another exit, because they can pick the weakest item and contest that one.

Then, if there's a consequence, make it one you'll carry out, and carry it out without drama. "If the report's late again, I'll have to take you off the account." A small consequence that happens is worth far more than a large one that's shouted and then forgotten.

Be careful with this one at home. Between adults, a consequence is something you'll do to look after yourself, such as eating without them or no longer lending the car. It isn't a penalty you hand down. If you catch yourself designing punishments for a partner, you've gone back to winning by fear, only in a quieter voice.

Nothing on that list requires you to be pleasant, or to pretend you aren't angry. "I'm very angry about this" is a perfectly good sentence, and it carries more weight when said quietly by someone plainly in command of themselves. You can also refuse, stop lending money, leave the room, and in the end leave the job or the relationship. Anger is often the thing that tells you it's time for one of those. Keep that. I'd only say that decisions of that size should be made on the twentieth minute or the twentieth day. The first minute is the wrong time for them.

Some situations can't be fixed by any way of speaking. If you've stated a boundary calmly and clearly several times and it's been ignored each time, the other person understood you perfectly well. They aren't going to change, and what you have to decide now is what you'll do about that. Your volume has stopped being the question.