Authenticity

I believe a writer's first obligation is to be truthful. That doesn't mean historical correctness. Dramatic truth is not necessarily reflecting reality. What it demands is the writer's honesty. For one, he must not write about things he does not know nor understand. Even fictious characters and situations must be understood. If you write about, let's say, a day in a policeman's life you have to understand how policemen spend their days. The same applies, and even more so, to emotions. If you don't believe in true love, you'd better write about kung-fu, provided you're familiar with it. What you write about something you don't know can only be a cliché.