Fear of silence

I've often wondered why we feel awkwardness when there's gaps in the conversation. Why do we begin to feel anxious as if the other person is judging us, and we begin to judge ourselves negatively, causing us to feel even more judged, and this turns into a negative feedback loop.

What's so scary about silence? It can conjure the bad and the good, yet the bad is the easiest to focus upon. Ever been alone in a pitch black basement? The first thing we think of is danger, because it's the most immediate concern to our survival instincts. Our primitive instincts lead us to fear the void, and we try to hide these instincts by distracting ourselves with other thoughts and pursuits. 
As Alan Watts beautifully stated: 

"If you talk all the time, you will never hear what anybody else has to say, and therefore, all you'll have to talk about is your own conversation. The same is true for people who think all the time. That means, when I use the word 'think,' talking to yourself, subvocal conversation, the constant chit-chat of symbols and images and talk and words inside your skull. Now, if you do that all the time, you'll find that you've nothing to think about except thinking, and just as you have to stop talking to hear what I have to say, you have to stop thinking to find out what life is about."

Awareness is the ability to perceive your own thoughts objectively, and this can't occur until we stop and accept the void. We'll continue to be afraid of loneliness, and our own thoughts, if we keep running. Awareness and objectivity are the prerequisites for improvement, since we need them to identify problems (and therefore improvements) in our own thinking patterns and actions.