Check out “Do you and your lizard live in a van down by the river?” at Cubicle Nation. It’s a great blog about the Lizard Fear of people.
Lizard Fear
Martha says in Steering by Starlight:
The entire purpose of your reptile brain is to continually broadcast survival fears- alarm reactions that keep animals alive in the wild. These fears fall into two different categories: lack, and attack. On one hand, our reptile brains are convinced that we lack everything we need: we don’t have enough time, money, everything. On the other hand, something terrible is about to happen. A predator– human or animal–is poised to snatch us! That makes sense if we’re hiding in a cave somewhere, but when we’re home in bed, our imaginations can fixate on catastrophes that are so vague and hard to ward off that they fill us with anxiety that has no clear action implication.
“Successful people have all the luck – I just get bad breaks.”
“Lizard Fear” Example
The Human Lizard
Animals will live longer when obsessed with getting more resources and avoiding danger. Humans carry that same instinct, but without facing the same dire situations. This leads us to act in all kinds of unpleasant ways, including paranoid, greedy, suspicious and desperate.
It’s very common for people who are making significant career or life changes to have a lizard fear. It doesn’t matter how much experience they have or how much money sits in their bank account, they feel as though one wrong move will utterly destroy their lives.
The Van by the River
You might like the following Saturday Night Live sketch which relates to the part of “Do you live in a van down by the river?”
Karim Vaes 
Updated link : http://www.escapefromcubiclenation.com/2008/05/22/do-you-and-your-lizard-live-in-a-van-down-by-the-river/