I Don't Know is a strong term in our language. It's capable of conveying frustration, ignorance (chosen or otherwise), or pure wonder and curiosity.

Yes grants permission. Yes opens doors. Yes volunteers you to the service of others. Yes gives money. Yes gets you a date with the hottest person in your class.

There are few things more powerful in the English language than the word "No". Some people just can't say it. Some people just can't stop.