Loss of natural resources or poor management of them. Robs people of the resources necesary to provide for themselves.
Loss of ambition. This one can be exacerbated by government hand-outs.
Loss of opportunity. Without an opportunity, there's nothing.
Poor attitudes. If a person's atitude is wrong, they can't/won't see many opportunities. Even lack of education can be overcome- with the right attitude education opportunities can be found.
Government policies. One example- communism robs people of the motivation to work. If I know that I will be paid next-to-nothing whether I work hard or do little... why should I work at all?

