Why is fear such a dominate force in so many people's lives?

I have written about fear many times.  My belief that fear is an outward manifestation of an inner lack of faith.  Scripture tells us that fear and faith can't live in the same body.

So why is fear such a dominate force in people's lives?  Check out the following Scripture.

Mark 9:5-6(NKJV)

Then Peter answered and said to Jesus, “Rabbi, it is good for us to be here; and let us make three tabernacles: one for You, one for Moses, and one for Elijah”—

because he did not know what to say, for they were greatly afraid.

Mark 9:30-32(NKJV)

Then they departed from there and passed through Galilee, and He did not want anyone to know it. 

For He taught His disciples and said to them, “The Son of Man is being betrayed into the hands of men, and they will kill Him. And after He is killed, He will rise the third day.” 

But they did not understand this saying, and were afraid to ask Him.

What struck me in these verses was that even the disciples let fear control them to a certain extent.  Let's take the first Scripture for example. 

Peter, James, and John go up the mountain with Jesus and they see Moses and Elijah and the disciples are afraid.  Why???  Why were they afraid?  They were with Jesus.  What was there to fear?

In the second Scripture they were afraid to ask Jesus to explain something.  Again, why???  Why would they fear asking Jesus anything?  Did they really think Jesus was going to bite their head off or something just for asking for an explanation? 

I hear people all the time talking about their fears.  For me it is like hearing fingernails on a chalk board.  I had a conversation with a young lady recently and all she talked about was her fears.  After about 5 minutes I asked if I could offer her some advice.  She said yes.  I told her "stop talking about your damn fears all of the time.  The way you talk, I'm amazed you can even get out of bed in the morning.  Stop letting fear control your life!"

But reading the above Scripture and seeing how much even the disciples were controlled by fear it got me to wondering why fear is such a strong influence.  I believe the Holy Spirit has given me the answer.

One of the strongest responses in the human body is the fight or flight response.  It is our survival mechanism that is hard wired in us.  So fear is a very natural response.  But it is also a response that we need to learn to harness and control. 

That is where faith comes in.  Faith is a decision.  Just because we are Christians doesn't makes us immune to our body's natural responses.  The difference should be in how we respond to fear.  We need to develop the discipline to recognize fear and immediately insert our faith over that fear. 

Does that make sense?  It is a bit of a change in thought for me.  I had it in my mind that Christians should be able to totally preempt fear.  Noticing today how the disciples were controlled somewhat by fear even though they were with Jesus Himself, helped me see the error in my thinking.  Pretty cool how the Holy Spirit leads us in our daily walk as long as we keep seeking!