You must never be stupid enough to say, or smart enough to admit, you "know" what someone else is talking about. The moment you do your learning stops.

Generally speaking, the ego encourages you to constantly prove yourself and what you already know. When you are in the presence of someone you feel the need to impress, the ego's automatic response is "I know."

When your in the presence of someone your ego thinks is smarter, richer, more experienced than you, your ego tells you, "I know what they are thinking about me."

When your in the presence of someone your ego believes is not as smart, rich or experienced as you, "I know" is the way to cut them off.

The moment you say "I know," you are demonstrating that you don't know. You can learn something valuable from everyone, in every situation.

I Am open and willing to learn.