All of us prefer to be told the truth - at least we say we do - even when the diagnosis is terminal. And doctors believe they have an obligation to deliver bad news except that often they don't. In a survey of nearly 2,000 physicians by the Mongan Institute for Health Policy at Massachusetts General Hospital, a majority said they believe they should never lie to a patient, and yet more than half delivered a rosier prognosis than warranted, and 10 percent outright lied. Telling somebody they're about to die isn't easy, of course, and it's no easier having what's sometimes called the conversation with their loved ones.