Quote from : Story: Style, Structure, Substance, and the Principles of Screenwriting Book

We realize we can't go around saying and doing what we're actually thinking and feeling. If we all did that, life would be a lunatic asylum. Indeed, that's how you know you're talking to a lunatic. Lunatics are those poor souls who have lost their inner communication and so they allow themselves to say and do exactly what they are thinking and feeling and that's why they're mad.