It’s been said that the most powerful tool for physical health is a fork (or spoon), since the choices you make with it determine the good or bad things you put into your body.

In the same way, perhaps the most powerful tool for your mental health – and certainly for the health of your relationships – is your tongue. Thousands of times each day, it (or your fingers on a keyboard: same thing) offers the good word or the bad one out into your world.

If you say what’s true for you, and say it clearly and kindly, you get one kind of results. But if you use a sharp tongue, …