Pirkei Avot 1:9

"Shimon ben (son of) Shatach said: Examine witnesses thoroughly and be careful with your words lest through them they learn to lie."

One one level this is advice to judges.  As such, it makes sense: to determined the truth, a judge must ask many questions, in a way that doesn't reveal the answers he suspects.

But it seems to me that this mishna is not just about advice to judges.  We are all judges of hundreds of questions, issues and challenges that arise daily, and the people we interact with daily are witnesses of events that are the basis for our decisions and our actions.  On this level, this mishna is about how to interact with others and how to live.  By the questions we ask, and the way we ask them, we learn about the world and those around us.  When we come to life with preconceived notions and fail to inquire earnestly about the problems and decisions we face, we live errantly.  To live seriously, we must be aware of those around us, and learn from them, and take our decisions in our daily lives as seriously as judges take their decisions.  There is a point to this: living justly every day, to the best of our ability, matters, perhaps as much as anything else.