There are many times I hate to say that I don't know. It is a necessary by-product of hard work in academic research and honesty in character building. I'm glad for this quote (Joshbot):
"As someone who is an expert in a tiny "portion of the elephant," and applies this expertise to the public at large, I think you make some accurate points. For my job it's important to understand that there are things I know, things I think I know (with varying degrees of certainty), and things I don't know. One of the main sources of tension comes from being honest about not knowing. The majority of people do not want to know how much is unknown about their particular problem, and sharing this truth with them generally results in anxiety. Personally, I think inducing some anxiety is better than being fraudulent."