I once made the silly mistake of suggesting that members of the Church might beneficially learn from non-LDS sources, or more specifically, that non-LDS sources might have messages for people in the world, messages from God that could only viably come through them and not from our own leadership. The sentiment itself might not sound so objectionable to most Mormons. My mistake was that I made this suggestion during a Sunday School lesson. And I compounded my error by later reading a quote from a non-manual source.