Imagine you are a virtuoso musician or an actor: after a concert or a theatre performance ...

"Imagine you are a virtuoso musician or an actor: after a concert or a theatre performance you receive a hundred or so letters congratulating and thanking you. But there in this large amount of post you find a single unpleasant letter. What happens? All the expressions of esteem and admiration will be overshadowed by this one negative letter, which acts like a poison. There is just one poisonous letter, and the others, in spite of their much greater number, are not able to neutralize it.

So do give that plenty of thought, and when you need to write to someone, blaming or criticizing them, be careful to weigh all your words. A letter is something very important; if you are not aware of this, you are likely to cause a great deal of damage in other people's lives, as well as destroying many good things in your own life."