[jqm]

I can tolerate know-it-alls when they really do know a lot more about something than I do and are willing to share.

However in my experience, the majority of people with a know-it-all attitude are simply blowing hot air and trying to cover for the fact that they really aren't nearly as smart or knowledgeable as they would like to be.

Most truly smart and knowledgeable people I've met have been amazingly humble and usually fairly quiet about things. The qualities of quietness and humility lead to learning.