Fear God?

A theme that runs through the Proverbs and the whole Bible is the fear of the Lord.  The fear of the Lord is a term many wrestle with; scriptures like ‘the fear of the Lord is the beginning of knowledge,’ and ‘the fear of the Lord is the beginning of wisdom.’
 
Why is the fear of the Lord so important, and what is it?  
 
The fear of the Lord is a life rearranging, joyful, awe, and wonder before the greatness of who God is and what he has done. So why use the term fear?

Read: Proverbs 3:5-6; 9:10; 16:6; 19:23; 20:9