Afraid of a tomorrow that carries no guarantees. Afraid of the new and the different. Afraid to risk an open and uncertain future. And without that absolute security, they are turned into bugs. Only slavery offers absolute security, absolute certainty.
Fear is one part of the problem.
But for most of us, it is much more prosaic. The most common word for sin in the Jewish tradition is the Hebrew, h et . The word comes from archery. H et literally means missing the mark, missing the target. This is not a failure of intent, nor a failure of fundamental morality.