If you are sensing that I am posting this out of disagreement. You couldn't be more right. :p I recently attended a so-called meeting and one of the speaker said something along this line.
"You cannot say "I don't know.I don't know means I am stupid."
To make it fair for the speaker, the next sentence was "You cannot not know anything. If you do not know, say you will find out."
Anyway, I'm still not happy with the first sentence. Here's my perspective.
It is good that you know what you do not know. It is great that you admit that you do not know something. *Rather than let ur ego do the acting.* The worst place anyone could be in is : To not know what they do not know. Raise your hand if you disagree! Til today, some of my colleagues are mimicking the sentence. LOL!
I am stressing here that it is ok to not know something and to admit that you do not know. =)
If you do not know something, ask. Keyword is ASK. =) IF you pretend to know something that you do not know, not only you will be in trouble but you might be affecting others who are working with you too. ;)